Linux libc-Doku

Files | Functions
Strings

Files
file   string.h
 

Functions
size_t  strlen (const char *s)
  Calculate the length of a string. More...
 
char *  strcpy (char *dest, const char *src)
  Copy a string. More...
 
char *  strcat (char *dest, const char *src)
  Append a string to another string. More...
 

Detailed Description

The functions in string.h allow for an easy manipulation of C strings. Always remember to allocate the memory for the trailing \0 after a C string and be aware, that strlen() does not include the terminating \0 in the string length.

// allocate some memory
char string_a[5+1], string_b[7+1];
char string[5+7+1];
// copy substrings into memory
strcpy(string_a, "Hello");
strcpy(string_b, " World!");
// concatenate the two strings
strcpy(string, string_a);
strcat(string, string_b);
printf("%s", string); // $> Hello World!
// determine the length of the concatenated string
size_t siz = strlen(string); // siz = 12 (5+7)
printf
int printf(const char *format,...)
Print formatted data to stdout
strcpy
char * strcpy(char *dest, const char *src)
Copy a string.
strlen
size_t strlen(const char *s)
Calculate the length of a string.
strcat
char * strcat(char *dest, const char *src)
Append a string to another string.

Function Documentation

size_t strlen ( const char *  s )

The strlen() (string length) function calculates the length of the string pointed to by s, excluding the terminating \0.

Parameters
s string under test
Returns
number of chars in s

char* strcpy ( char *  dest,
const char *  src 
)

The strcpy() (string copy) function copies the string pointed to by src, including the terminating \0, to the buffer pointed to by dest.

The strings may not overlap, and the destination string dest must be large enough to receive the copy.

Parameters
dest buffer, where to copy to
src buffer to be copied
Returns
pointer to dest

char* strcat ( char *  dest,
const char *  src 
)

The strcat() (string concatenate) function appends the string pointed to by src to the string pointed to by dest. Thereby, the terminating \0 of dest is overwritten. The concatenated string in dest is terminated by a \0 again.

If dest is not large enough to include both strings, the program behavior is unpredictable.

Parameters
dest buffer, where to append to
src buffer to be appended
Returns
pointer to dest