The strcat() Function The strcat() function concatenates two strings. It appends a copy of the source string to the end of the destination string, and then returns the destination string. This function also require including the string.h library file. This syntax of the strcat() function is: Syntax: char* strcat (char* strg1, const char* strg2) The behaviour of strcat() is undefined when the size of the array pointed to by strg1 isn't long enough to accommodate all the characters from strg2. Difference between Argument and Parameter in C/C++ with Examples. It is recommended by many of the programmers that strncat() is safe as compared to strcat() because strcat() does not check for the size of the copied data, and copies until it gets to a null terminator, it might cause a buffer overflow The strcat() is a string manipulation function defined in the string.h header file, which works on a string which is stored in a c-style char array. This function is used to add or concatenate two strings by appending a string at the end of another string. Concatenate strings - References for strcat with worked examples. The strcat function is easily misused in a manner which enables malicious users to arbitrarily change a running program's functionality through a buffer overflow attack. Appends a copy of the character string pointed to by src to the end of the character string pointed to by dest. The character src[0] replaces the null terminator at the end of dest. The resulting byte string is null-terminated. Prototype: char *strcat(char *Destination, char *Source); Header File: string.h (C) or cstring (C++) Explanation: This function will concatenate (add to the end) the string pointed to by source on to the string pointed to by Destination. A short video lesson on using strcat, and how to append strings. I review the strcpy function in this video, as well as how to use strcpy and strcat together. iTextSharp is open source PDF solution. In most of the examples below, I tried to alter,copy a template PDF and then save it into a brand new output PDF file. It's easy to work with PDFs , when we have a basic template (created externally using Adobe/OpenOffice) in place, -- instead of generating a new Strcat has no way to validate destination buffer length thus programmer should provide a buffer which is at least the combined size of source string and destination string (destination buffer size >= source string + destination string). If destination buffer is smaller than it can corrupt data or heap segment In computing, the C programming language offers a library function called strcat that allows one memory block to be appended to another memory block. Both memory blocks are required to be null-terminated.