Copy buffer to struct in c. Apr 22, 2011 · Structures which contain pointers to (within) themselves, or which contain pointers to data that should be deep-copied. Therefore, you cannot safely append to it with strcat(). The reason I am trying to do the conversation is to send this uint8_t buffer as a parameter to a function. [StructLayout(LayoutKind. The number array has negative and non-negative values. dns_buf is not a string (which finish with null charcter). GetBytes(str); You probably want to check to see if the size of the string isn't longer than the size of the buffer. as you can see its not easy and not portable, because we need to extract the data as per the boundaries of memory, allocated for variables. How do I convert this struct in to a unint8t array in C++ on the Linux platform. Have the first struct byte/short/int of all structs you pass around by convention hold a tag that tells the other end what type is coming along. Create a Buffer. I've already tried this and it doesn't work. Basic implementation. data = (char*)malloc ( (strlen (buffer) + 1) * sizeof (char)); strcpy (var. You should likely maintain buff as an array of unsigned char rather than int. union{. This is what I have: #define MAX_FILES 12. C Stucts and Pointers. I wrote a code but it doesn't work. How do compilers achieve that? I. Then you give memcpy pointers to the source and destination locations. For Example, in C language, the data entered using the keyboard is first stored in the input buffer, and then it is stored in the memory. That said, it is possible that you can reuse the functions. compared to a call to memcpy? Now consider this code: struct X { int i, j, k; }; void foo(X x); void foo( int i, int j, int k); May 10, 2013 · The struct is at the beginning of the buffer, and i want to copy it to a struct defined in the code, THdr Struct_copy. struct members aren't necessarily contiguous memory so your best bet would be to copy the appropriate byes from data to each struct or class member individually. s2 -> grade = s1 -> grade; printf("weight: %f", personPtr->weight); return 0; } Run Code. void *buffer; // data buffer. When you copy the int, at least one of the first "n" characters of the buffer will be zero (where "n" is the size of an int on your platform). The struct keyword is used to define the structure in the C programming language. p2. By the way I found way to type cast from char* to struct. pYro_65 August 5, 2014, 11:07am 3. typedef struct bufDataType {. void *buffer_end; // end of data buffer. The function takes two arguments: a destination buffer where the copied string will be stored, and a source string that will be copied. Transferring pointers between applications is just a speed test between different compression methods in the end. Parameters DataToSend[1]={{queue1,&buffer}}; queue1 is an object and so is not a constant expression; it is not valid in C89. And, if your C implementation doesn't have a strdup (it's not part of the ISO standard), get one Sep 7, 2013 · In your code, change: struct msg_struct {…} to: struct __attribute__ ((__packed__)) msg_struct {…} You will also need to correct the pointer arithmetic. I can't solve the problem, obviously, I indicated wrong parameters in push and Mar 10, 2009 · I'm looking for language support of serialization in C#. The ASCII character set, for instance, is only 7-bits. The C++ language however only allows conversion of void* to a pointer type. unsigned char buf[SIZE]; } bufData; static struct {. If you want to copy the data, then do so. to see the dns_buf content you can use: Oct 10, 2011 · The problem was indeed in my failure to initialise the structs correctly. In the case of BitConverter you would also need to use Buffer. System. Feb 13, 2016 · 193. char* name; }; char buffer [SOMESIZE]; struct data var; var. – Jul 22, 2010 · In order to copy the entire content you have to allocate memory to the pointers of the struct p2. To access a structure variable you can use the point like in stu. Dec 10, 2021 · memcpy() simply copies data one by one from one location to another. Example. Text. Jul 19, 2018 · I'm receiving byte buffer array and trying to copy it to a structure: my structure is: uint8_t cmd; uint32_t param; char str_buf[10]; uint32_t crc32; first, the program that sends the data as following: when the data is recieved im copying the data to the structure using the memcpy code below: memcpy((uint8_t *)&blockRX,(uint8_t *)usbd_cdc Feb 9, 2011 · Also, struct assignment is legal in C, so you could just do: newnode->keys[i] = clsf_ptr; Note that both of these approaches only do a shallow copy. To avoid overstuffing our mailboxes, we use strncpy: // 👇 Copy source buffer to target buffer char buff[6]; strncpy (buff, "helllo is extra hello", sizeof (buff) - 1); buff[sizeof (buff) - 1] = '\0'; strncpy carefully places letters in the mailboxes, making sure not to overflow and mess up the neighborhood (our memory). This won't work reliably. it will only copy the pointer values. I want to copy the data of structure into a buffer. "Command_Data* tmp_str = reinterpret_cast<Command_Data*> (buffer);" Now, gotta copy this data into [Command_Data message buffer]. However, I would prefer a more automatic way like one could do in C/C++. Jun 19, 2011 · The C++/CLI compiler is a bit obtuse about this. Nov 3, 2012 · 1) The hard way: For a deep copy you'll need to traverse the entire structure and recreate it one node at a time. So if struct classifier has pointers to memory, the pointers themselves will be copied, rather than creating new copies of the memory. BlockCopy to copy the remaining data of the byte array to the byte array field in your class. position[1] = 5. – Ian Abbott. Mar 20, 2013 · The problem is, with any approach, all you will get in C is the member name as a string (either with using a table or a userdatum with an __index metamethod). Jun 29, 2009 · Does endianness affect the byte order of the struct as a whole, or of each individual member of the struct? What approaches would I take to convert a struct created on a unix system to one that has the same data on a windows system? C89 requires the initializers of a structure object (and more generally for objects of aggregate and union types) to be constant expressions. #include <stdint. Code. On the other hand memmove() copies the data first to an intermediate buffer, then from the buffer to destination. This is because memory is not allocated in a contiguous manner. memcpy only works is all the data related to the struct is stored in the struct. Module 1 provides data in a shared_ptr of a struct, while module 2 needs data in a &quot;normal&quot; struct. Mar 19, 2009 · 2. uint8_t firstName[4]; Parse the fields individually and end each field with '\0'. The strings may not overlap, and the destination string dest must be large enough to receive the copy. node traverse_cp(node, checked_list){. Nov 7, 2012 · Copying data of Structure into a buffer. Dec 7, 2023 · The class basic_streambuf controls input and output to a character sequence. You haven't allocated any space in your output array to put the copy into. struct GetResultStructure { int length; char* ptr; }; I need a way to make a full copy of it meaning I need a copy to have a structure with new ptr poinnting on to copy of data I had in original structure. {. In the following example, the two assignments make two very different things: struct Type *s1,*s2; *s1=*s2; s1=s2; Inadvertently using one instead of the other may have disastrous effects. e. Jan 31, 2011 · so I have a structure like. Similar to memcpy in C/C++. h>. Now, you can access the members of person1 using the personPtr pointer. Mar 3, 2023 · strcpy is a C standard library function that copies a string from one location to another. #pragma pack (0) or the gcc option -fpack-struct [=n] are a couple of ways of controlling this. You do not want a pointer to the array, but a pointer to the first element: radio. , in a variable). I aksed about your file format since some of your struct members were ints and you cannot have ints in a text file. You don't have to copy buffer to struct, assigning a pointer to buffer is the efficient way to parse buffer into struct. so instead of all memcpy s you just assign the ponter to the buffer, For example: #include <iostream>. For e. When passing a struct in C/C++ by value the struct contents must be copied. You're copying from &i as if that was the pointer to a string, when in fact it points at a struct whose first field is an int. Both srcOffset and dstOffset are zero-based; that is, the first byte in each buffer is at position 0, not position 1. h> header file. b = Buf[1] | (Buf[2] << 8); /* assuming little-endian */ r. void copy_Student(Student *s1, Student *s2) {. BlockCopy() for same-type array copying can be found here. BlockCopy(). May 10, 2019 · The thing that you want to copy (e. The CLI supports pointer types but there are very few framework methods that accept them. The structure in C is a user-defined data type that can be used to group items of possibly different types into a single type. when I print the fields, I get some big value which isn't the correct one. Here is the code I wrote. a = Buf[0]; r. I have defined the structs for the required information and trying to use memcpy to copy the buffer information into the struct. The simplest solution would be to keep track of the item size and the number of items, and then create a buffer of the appropriate number of bytes: typedef struct circular_buffer. Dec 8, 2022 · I've a setup where I need to exchange data provided in structs between two modules . There is also a shorter way to assign values to a structure: typedef struct{ int x; int y; }point; point image_dimension = {640,480}; Dec 27, 2018 · I want to create a circular buffer using structs in c++. age. May 18, 2013 · In obtain_name_affiliation, make a char buffer[1024] to read data into. g. Better still, use an std::vector<CharMapT>, use std::string for CharMapT::name, and use std::copy() to replicate the source (or even direct-assignment). We can also use buffers of other types such as int or double. Sep 7, 2009 · While this scenario is not common, Array. I could derive from ISerializable and implement the serialization by copying member values in a byte buffer. More generally, you ought not be manipulating general data with string functions. Nov 8, 2012 · memcpy is preferred because it makes it clear the programmer wants to copy the content and not simply the pointers. Depending on the endianness of your processor. position[0] = 1. I am having problems inserting elements to the buffer. Then write a function to copy them which checks the capacity, copies the size (but not the capacity), and copies the data. CFile oFile; Aug 20, 2015 · What's the most simple way to read and write data from a struct to and from a file in c++ without serialization library? 0 read/write struct from text file in c++ Feb 7, 2013 · 4. Ignoring the obvious typo, struct ExampleStruct *exampleStruct = (ExampleStrcut) *buffer; should be struct ExampleStruct *exampleStruct = (ExampleStrcut *) buffer;, the second example is illegal. The basic idea behind a deep copy is that you have to copy each field; for non-pointer types this is the same as a shallow copy, but for pointers you have to do something smarter. Dec 9, 2023 · To answer your question yes, it does work but that is due to the implementation of std::vector<char>. , some foobar_t* pointer) has to be stored in a location (e. – Karl Knechtel Apr 27, 2011 at 17:01 Sep 4, 2019 · The layout of the array and structure are identical, meaning that the compiler does not align either the items in the array or entries in the structure. The first part covers C programs, compiling and running, variables, types, operators, loops, functions, arrays, parameter passing (basic types and arrays), standard I/O (printf, scanf), and file This method copies count bytes from src, beginning at srcOffset, to dst, beginning at dstOffset. Now my task is to write a simple ring buffer. The first way is definitely wrong as hdr is an uninitialized pointer. memcpy() leads to problems when strings overlap. char a1[10]; Apr 26, 2013 · 1. Feb 15, 2013 · 4. This works, and I can theoretically also decode this. size_t capacity; // maximum number of items in the buffer. Something like this: Jun 3, 2018 · 0. 2; element. Copy() can perform very poorly here due to the continual "safe" value type casting, compared to the direct casting of Buffer. // C# to convert a string to a byte array. Copy complete structure in a byte array (character buffer) in C. The code you posted, however, isn't doing that. char Jan 28, 2016 · You can copy the structure into a buffer as follows. So its a waste. Visual Studio also has an option in the GUI to set the structure padding for your project. This is why you should use std::copy, it will behave correctly irrespective. ) Jun 30, 2018 · What you are printing is a pointer, the address of the buffer. Copy individual struct members instead of a memcpy of the entire struct. We will copy structure person into a character array (byte array) buffer and then print the value of buffer, since buffer will contain the unprintable characters, so we are printing Hexadecimal values of all bytes. uint8_t four:4; bool empty:1; bool b:1; uint8_t two:2; }; I am no fan of bit fields, but they seem to be applicable in your case. I think I need to copy the data in the buf instead of pointing to the buf because it will be overriden whenever a new data comes in. It is declared in <string. buffer_name - name of the buffer. name. I used memcpy () function but it doesn't work, as structure has padding problem. Marshal::Copy() doesn't. Nov 7, 2017 · No, that's undefined behaviour. data, buffer); var now has a copy of the data. The fixed size buffer is declared in a struct (Later I'll need to send all the content of the struct at once). . Feb 2, 2024 · I would prefer to use an instance of MyStruct to be directly filled by "recv_from" instead to using a u8 buffer and then deserialize the received bytes to the instance struct in order to avoid the copy operation. A third way, also generally the fastest way, is to convert your class to a struct and use unsafe code to cast the byte array as that struct. Jan 28, 2019 · Thank you, but the code posted already is pretty much all of it. you can simply write update_packet instead of struct update_packet. I know that i can use memcpy(&Struct_copy,data[0],sizeof(Struct_copy)); but i would like to use a "C++ style" way, like using std::copy . Jul 28, 2016 · Since your code is not portable anyways, you might as well just use bit-fields here: struct sample {. – Mark Hendrickson. #include <stdio. If not, write null values into the buffer at the end of each entry and store the pointers to the start of each in your struct. Circular buffers (also known as ring buffers) are fixed-size buffers that work as if the memory is contiguous & circular in nature. To easily access the bytes, I implemented the struct with unions: typedef struct{. I am unsure which function would be best to solve this issue. Jul 1, 2013 · 4. For example, consider below program. Feb 1, 2020 · As you can see in this example you are required to assign a value to all variables contained in your new data type. May 30, 2023 · 1. C99 changed this rule and allows structure initializers that are not constant Aug 14, 2015 · I have sflow packet capture code in which I need to print the sflow data information from buffer. About serialization: you are copying the struct over the buffer, with padding and all. I receive the bytes over socket and they are the bytes of the same struct abc variable. The controlled character sequence, also called the buffer, which may contain input sequence (also called get area) for buffering the input operations and/or output sequence (also called put area) for buffering the output operations. read(&myRXbuffer, 32); //Needs to be. Instead of copying the entire buffer in one go, copy the elements one by one. Try this instead: *((char *) &struct_data + i) This converts the address of struct_data to a char * and then adds the index, and then uses the dereference operator (unary *) to get the "char" at that address. c = &Buf[3];. Jan 22, 2019 · Modify your structure. Mar 20, 2017 · I just started learning C language. The function copies the entire source string, including the null terminator Mar 7, 2016 · That buffer is just a prototype of send function. If you do those three things separately then you don't have to worry about layout. It's a nice idiom. while(*animals) {. Apr 19, 2013 · The struct1=struct2; notation is not only more concise, but also shorter and leaves more optimization opportunities to the compiler. Nov 26, 2013 · The best way is by using the range copy constructor and a low-level cast to retrieve a pointer to the memory of the structure: auto ptr = reinterpret_cast<byte*>(&s); auto buffer = vector<byte>(ptr, ptr + sizeof s); To go the other way, you can just cast the byte buffer to the target type (but it needs to be the same type, otherwise you’re Feb 27, 2012 · I'm trying to copy data into a unsigned char buffer within an array of structs inside one global struct, but it's somehow failing. personPtr->weight is equivalent to Jul 16, 2011 · Now, if I make buffer global or static, then I can rx the whole string. void *buf = calloc(1000, 1); memcpy(buf, s, sizeof(s)+ s->size); Print out the names as follows to check it worked. hand this pdata to the thread pool to parse and handle it. Mar 12, 2022 · i'm relatively newer in C and i have some problems to memcpy a struct in a buffer; I have this struct: `typedef struct { uint8_t size_of_payload; uint8_t command; unsigned char* payload; }__attribute__((packed)) mystruct`` and i want to copy in a tx_buffer[SIZE] the values of this struct, including the value pointed by payload. My excuse is simply that I'm used to working with struct pointers, not structs, and so writing. ocl_element_2d_t element = host_buffer[i]; element. If you want copies of the data then you must raw-allocate them (malloc, new, whatever). It is written specifically for CS31 students. August 18th, 2011, 11:22 PM #3. As memory is … Continue reading "Creating a Circular Buffer in C and C++" This always stays the same, so I can assume it without any delimiters between the values. Right now I do something like. – legends2k Nov 21, 2014 at 7:04 Jun 17, 2011 · pushWork(char * pdata){. Dec 8, 2012 · takes the address of struct_data and increases it by i times the size of the structure. Let's consider the example Aug 5, 2014 · If you simply cast the myCurrentsMessage instance, then you probably could get away with using memcpy () to copy the buffer to the struct instance. Thank you. Appreciate some help on this. Mar 16, 2017 · How can we copy an unknown size buffer into a fixed buffer in c? For one of my functions, I'm trying to copy an unknown size buffer into a fixed buffer (of size 1024 bytes). In this example, the address of person1 is stored in the personPtr pointer using personPtr = &person1;. Adding header_size to buff adds the distance of 100 int objects, because buff is a pointer to int. char buffer[(sizeof(struct Astructure))]; to. if my replace this. Add an extra byte to each field to accommodate the '\0' character. 0) . The items in the structure are called its member and they can be of any valid data type. By assigning to r->c, you are both clobbering the very buffer contents you are trying to point to and writing past the end of the array buf. For non-POD types and types for which std::vector has a particular template specialisation that affects the memory layout ( std::vector<bool> ), it will not work. here's a simplified pseudo code example. For instance, if I have two structs A and B where A contains B, I can have two serialize methods: char* serializeB() { // Dec 14, 2015 · Step 2: Copy Text Safely. The formal definition of IntPtr is "native integer", it is not a pointer type. Using the C++ style casts guarantees you get the cast you intend; the C-style cast basically just tries a sequence of five different types of casts until it finds one that works. Mar 10, 2017 · The struct representation that you copy into the buffer is not collectively the contents of a C string, if only on account of having internal null bytes. memcpy (dest_struct, source_struct, sizeof (*dest_struct)); dest_struct->strptr = strdup (source_struct->strptr); This will copy the entire contents of the structure, then deep-copy the string, effectively giving a separate string to each structure. use. The semantic meaning of = is an assignment, while memcpy just copies memory. Use =. So How am I supposed to declare my buffer here. Sequential, Pack = 1)] public struct abc { public int a; public int b; public float c; public char[] d; //30 size } Jan 4, 2021 · In the below program am copying the contents from the structure computers to unit8_t. Can anybody suggest me how to copy structure data into a buffer. This is the second part of a two part introduction to the C programming language. There's a few things: You're overflowing the buffer, char name[5] can't hold "Casey", the terminator won't fit. But make sure you use the pointers from the copy and not from the original data structure. 1. Printing out the zero will have the effect of terminating the output string. But, for the case of declaring as local, I do not get data back in my buffer. An example of how the program uses the buffer: data_buffer buffer = {0}; //Manipulate data here so it contains pertinent information. It includes and provides access to. ASCIIEncoding encoding = new System. That's a huge difference in readability as well, although memcpy does the same in this case. So, to copy 300 bytes from b to a where both a and b point to something useful, b has at least 300 bytes of data 95. uint8_t firstName[5]; instead of. Additional evidence from outside StackOverflow that Array. Co . I don't know of a way to return a struct's member just from having it's name in a string - unless you create some kind of table (or switch statement) that maps those strings to members/offsets - and you will have to do that explicitly Jun 25, 2010 · 1. nothing wrong with memcpy on a struct - as lng as the struct is filled with fixed-size buffers. #include <cstring>. We can create a buffer in C++ simply by allocating memory: char *buffer = new char buffer_name[buffer_size] Here, *buffer - pointer that points to the address of the buffer. For example for a 4-byte int: x00 x00 x00 x0a or x0a x00 x00 x00. Oct 10, 2013 · If I use memcpy to copy data from a receive buffer to this struct the copy is OK, but if i redeclare the struct to the following : Oct 7, 2010 · Any fields not specified are initialized to zero. Jul 12, 2022 · We can also use assignment operator to make copy of struct. You're initializing the first element of the array with a structure initializer that initializes the first element of the structure to zero. Oct 8, 2013 · void send_message(struct message *msg) { uint8_t *bytes = (uint8_t *) msg; /* call to write/send/sendto here */ } void receive_message(uint8_t *bytes, size_t len) { assert(len >= sizeof(struct message); struct message *msg = (struct message*) bytes; /* And now use the message */ if (msg->command == SELF_DESTRUCT) /* Jan 8, 2024 · In C, the buffer is referred to as a sequential section of memory that is used to temporarily store some data that is being transferred from one place to another. edited Jul 28, 2016 at 19:31. buffer_size - size of the buffer. My question here is that we are passing the address of buffer to the function, so it should not matter if it is local or global. The fastest way to copy a buffer to a struct is via memcpy (), and if you want to use the destination struct's members in a meaningful way you need it to be unpadded. int main() { User user = {"Naman", MALE, 21, 5}, user1; // Approach 3 user1 = user; printf("user: "); print_user(&user); printf("user copy: "); print_user(&user1); return 0; } Output. #define SIZE 512. For simple structures you can either use memcpy like you do, or just assign from one to the other: RTCclk = RTCclkBuffert; The compiler will create code to copy the structure for you. aamir121a. char *pdata = buf; pushWork(pdata) May 6, 2023 · C Structures. You can pass a char[] buffer into the function that has a whatever struct memcpy ed into it. That it's not portable, unless you serialize and de-serialize in the same computer. This gets rid of the function signature based on struct problem. Here's my struct definition: #define LENGTH_BUFFER 100 typedef struct { int buffer[LENGTH_BUFFER]; int head; int tail; } ringbuffer; ringbuffer test; Nov 12, 2015 · So I have a character array of fixed size: char buff[100]; And I have a character pointer: char *ptr; Now, the buffer will be filled partially or fully. The prototype for memcpy() is: void *memcpy(void *dst, const void *src, size_t n); and the description is that it copies n bytes from src to dst, and returns dst. Here I gave the size of my buffer before hand to the size of my structure. h header file. Nov 21, 2014 · In C++ struct types can be referred to independently, no need of the struct qualifier i. int counter; Jul 29, 2022 · The variables I want to add in the buffer is picked at random. Copy() is faster than Buffer. Try this instead. Oct 27, 2015 · Read the data into a buffer, parse it to find the token boundaries, and store the appropriate items. Aug 11, 2009 · 1. The memory associated with the struct and array are identical in size. By the way, personPtr->age is equivalent to (*personPtr). Variables of my structure is of unsigned char,intn and char type. Apr 17, 2015 · I have a ctypes structure (for example): from ctypes import * class Foo(Structure): _fields_ = [('f1',c_uint), ('f2',c_uint)] I would like to copy an instance of that structure in to a buffer that was created from create_string_buffer (that is larger in size than needed for a single instance of Foo). But as per my program I may not be adding all my variables in the buffer. name = <allocate memory>. using namespace std; struct clsA. This will NOT copy the data pointed to. Oct 30, 2023 · The memcpy () function in C and C++ is used to copy a block of memory from one location to another. 7; was the standard way to add properties to an object. Beware of buffer overruns! (See BUGS. The Strict Aliasing Rule allows you to view any object as an array of characters, but the reverse is not permitted. May 17, 2017 · 17 May 2017 by Phillip Johnston • Last updated 22 December 2022Due to the resource constrained nature of embedded systems, circular buffer data structures can be found in most projects. Unlike other copy functions, the memcpy function copies the specified number of bytes from one memory location to the other memory location regardless of the type of data stored. You are not concerned with portability to other architectures (which may change the answers to #1 and/or #2). The BlockCopy method accesses the bytes in the src parameter array using offsets into memory, not programming constructs such as Sep 3, 2010 · Your struct contains pointers as data members, this means you will have to roll out your own copy function that will do something sensible with the pointers. void p_init(const char **animals, char **output) {. If you have a struct with std::strings in there, create a stream operator and use it to format a buffer. I was referring to a situation in which unsigned char is < 8-bits. payload point to Sep 19, 2012 · If you're making such structs copyable, then in any case you should probably have a capacity as well as a size field in the struct. Nov 10, 2022 · I have a typedef struct with different data types in it. This structure basically acts as a buffer, with a pointer to the data stored within the buffer and the size of the buffer to allow the program to know how large the buffer is when reading from it. user: (Name: Naman, Gender: Male, age: 21, height 5. Nov 15, 2013 · Nov 15, 2013 at 7:15. uint32_t val; char bytes[sizeof(uint32_t)]; } recipientId; union{. You'll need to use malloc to allocate some space before using sprintf to copy into that buffer. You can then memcpy that buffer to the data transport. , which assembly instructions are usually emitted for this copy? How fast are these, when, e. Jun 25, 2015 · I have a struct abc and I want to copy bytes into a struct variable. This causes undefined behavior. May 19, 2011 · In C, you can copy memory from one area to another using memcpy(). The rest of the first structure and the rest of the array elements will all be zero too. ASCIIEncoding(); return encoding. Put a dynamic variable in there and you have to serialise it differently. Use buffer or &buffer[0] (for certain purists) as the targets in the string fscanfs; Use %1023s or the like to prevent the data read from overrunning the length of the buffer - overruns can drive your program insane. In f, you could do struct rec r; r. Oct 7, 2013 · @nightcracker2: You are thinking backwards. It is defined in the string. there is usually a compiler directive or #pragma to specify structure padding and alignment. Apr 22, 2010 · @Michael: That C-style cast is the same as the reinterpret_cast in this case, because no combination of static_cast and const_cast is valid. So here you have an array of structs. I changed it to array. An important note about the copying: It's a shallow copy, just like with memcpy. Finally, as far as "structs within structs" go, you will need to have several functions for each struct. Aug 18, 2011 · Re: Copy buffer to struct. it's a pointer (as char *) to a memory space and the memory could contains 0 as values at the beginning so that's why when you use strlen(dns_buf) you get it = to 0 that means the fisrt element in the dns_buf is 0. Aug 27, 2018 · The strcpy () function copies the string pointed to by src, including the terminating null byte ('\0'), to the buffer pointed to by dest. bc yg ad nu tj wc gb zs ha ki