Search notes:
libc: Strings and arrays
Functions that operate on arbitrary sizes of memory have names that start with mem* or wmem* (for example memcpy and wmemcpy).
Functions that specifically operate on strings and wide strings have names that start with str* or wcs* (for example strcpy and wcscpy).
str* and mem* functions are declared in <string.h>; w* functions are declared in <wchar.h>.
size_t strlen (const char * s);
size_t wcslen (const wchar_t *ws);
size_t strnlen (const char * s, size_t maxlen); // GNU extension, declared in <string.h>
size_t wcsnlen (const char *ws, size_t maxlen); // GNU extension, declared in <string.h>
char * strcpy ( char *restrict to const char *restrict from);
wchar_t * wcscpy (wchar_t *restrict wto const wchar_t *restrict wfrom);
char * stpcpy ( char *restrict to const char *restrict from);
char * wcpcpy (wchar_t *restrict to const wchar_t *restrict from);
void * memcpy (void *restrict to, const void *restrict from, size_t size);
wchar_t *wmemcpy (wchar_t *restrict wto, const wchar_t *restrict wfrom, size_t size);
void * mempcpy (void *restrict to, const void *restrict from, size_t size); // GNU extension
wchar_t *wmempcpy (wchar_t *restrict to, const wchar_t *restrict from, size_t size); // GNU extension
void * memccpy (void *restrict to, const void *restrict from, int c, size_t size);
char * strncpy ( char *restrict to, const char *restrict from, size_t size);
wchar_t * wcsncpy (wchar_t *restrict to, const wchar_t *restrict from, size_t size);
char * stpncpy ( char *restrict to, const char *restrict from, size_t size);
wchar_t * wcpncpy (wchar_t *restrict to, const wchar_t *restrict from, size_t size);
void * memmove (void * to, const void * from, size_t size);
wchar_t *wmemmove (void *wto, const void *wfrom, size_t size); // GNU extension
void * memset (void *block, int c, size_t size);
wchar_t *wmemset (wchar_t *block, wchar_t wc, size_t size);
char * strdup (const char * s); // use malloc to allocate new memory
wchar_t * wcsdup (const wchar_t *ws); // use malloc to allocate new memory
char * strndup (const char * s, size_t size);
wchar_t * wcsndup (const wchar_t *ws, size_t size);
char * strdupa (const char * s); // use malloca instead of malloc
wchar_t * wcsdupa (const wchar_t *ws); // use malloca instead of malloc
char * strndupa (const char * s, size_t size);
wchar_t * wcsndupa (const wchar_t *ws, size_t size);
char * strcat (char *restrict to, const char *restrict from);
wchar_t * wcscat (wchar_t *restrict to, const wchar_t *restrict wfrom);
char * strncat (char *restrict to, const char *restrict from, size_t size);
wchar_t * wcsncat (wchar_t *restrict to, const wchar_t *restrict wfrom, size_t size);
int memcmp (const void *a1, const void *a2, size_t size);
int wmemcmp (const wchar_t *a1, const wchar_t *a2, size_t size);
int strcmp (const char *a1, const char *a2);
int wcscmp (const wchar_t *a1, const wchar_t *a2);
int strcasecmp (const char *a1, const char *a2);
int wcscasecmp (const wchar_t *a1, const wchar_t *a2);
int strncmp (const char *a1, const char *a2, size_t size);
int wcsncmp (const wchar_t *a1, const wchar_t *a2, size_t size);
int strncasecmp (const char *a1, const char *a2, size_t size);
int wcsncasecmp (const wchar_t *a1, const wchar_t *a2, size_t size);
int strverscmp (const char *a1, const char *a2); // compares strings containing versions or indices - GNU extension
int strcoll (const char *s1, const char *s2);
int wcscoll (const wchar_t *s1, const wchar_t *s2);
int strxfrm ( char *restrict to, const char *restrict from, size_t size);
int wcsxfrm (wchar_t *restrict wto, const wchar_t *restrict wfrom, size_t size);
void * memchr (const void *block, int c, size_t size);
void *wmemchr (const wchar_t *block, wchar_t c, size_t size);
void * rawmemchr (const void *block, int c); // GNU extension
void *wrawmemchr (const wchar_t *block, wchar_t c); // GNU extension
void * memrchr (const void *block, int c, size_t size); // GNU extension
char * strchr (const char * string, int c);
wchar_t * wcschr (const wchar_t *wstring, wchar_t c);
char * strchrnul (const char * string, int c); // GNU extension
wchar_t * wcschrnul (const wchar_t *wstring, wchar_t wc); // GNU extension
char * strrchr (const char * string, int c);
wchar_t * wcsrchr (const wchar_t *wstring, wchar_t wc);
memcpy / wmemcpy / wmempcpy
The returned value of memcpy / wmemcpy is the value of the input parameter to/wto.
The returned pointer of mempcpy / wmempcpy points to the address right after the last byte written to in to (((void *) ((char *) to + size))) or wto.
The behavior of memcpy is undefined if from and to overlap. memmove should be used in such a case.
wmemcpy was introduced in Amendment 1 of
C90
strcmp / strcasecmp
#include <string.h>
#include <stdio.h>
void tq84_strcmp(char *a, char *b) {
int cmp_i = strcmp(a, b);
char cmp_c;
if (cmp_i < 0) cmp_c = '<';
if (cmp_i == 0) cmp_c = '=';
if (cmp_i > 0) cmp_c = '>';
printf("%s %c %s\n", a, cmp_c, b);
}
int main() {
tq84_strcmp("baz", "foo");
tq84_strcmp("baz", "bar");
tq84_strcmp("baz", "baz");
tq84_strcmp("baz", "FOO");
tq84_strcmp("baz", "BAR");
tq84_strcmp("baz", "BAZ");
}
In order to compare the strings case insensitively, strcasecmp might be used:
#include <string.h>
#include <stdio.h>
void tq84_strcasecmp(char *a, char *b) {
int cmp_i = strcasecmp(a, b);
char cmp_c;
if (cmp_i < 0) cmp_c = '<';
if (cmp_i == 0) cmp_c = '=';
if (cmp_i > 0) cmp_c = '>';
printf("%s %c %s\n", a, cmp_c, b);
}
int main() {
tq84_strcasecmp("baz", "foo");
tq84_strcasecmp("baz", "bar");
tq84_strcasecmp("baz", "baz");
tq84_strcasecmp("baz", "FOO");
tq84_strcasecmp("baz", "BAR");
tq84_strcasecmp("baz", "BAZ");
}
Apparently, the Windows equivalent of libc has a stricmp function instead of strcasecmp.
TODO
char * strstr (const char *haystack, const char *needle);
wchar_t * wcsstr (const wchar_t *haystack, const wchar_t *needle)
wchar_t * wcswcs (const wchar_t *haystack, const wchar_t *needle)
char * strcasestr (const char *haystack, const char *needle)
void * memmem (const void *haystack, size t haystack-len, const void *needle, size t needle-len)
size_t strspn (const char *string, const char *skipset)
size_t wcsspn (const wchar_t *wstring, const wchar_t *skipset)
size_t strcspn (const char *string, const char *stopset)
size_t wcscspn (const wchar_t *wstring, const wchar_t *stopset)
char * strpbrk (const char *string, const char *stopset)
wchar_t * wcspbrk (const wchar_t *wstring, const wchar_t *stopset)
char * index (const char *string, int c)
char * rindex (const char *string, int c)
char * strtok (char *restrict newstring, const char *restrict delimiters)
wchar_t * wcstok (wchar_t *newstring, const wchar_t *delimiters, wchar_t **save_ptr)
char * strtok_r (char *newstring , const char *delimiters, char **save_ptr)
char * strsep (char **string_ptr, const char *delimiter)
char * basename (const char *filename)
char * basename (char *path)
char * dirname (char *path)
void explicit_bzero (void *block, size t len)
char * strfry (char *string)
void * memfrob (void *mem, size t length)
char * l64a (long int n)
long int a64l (const char *string)
error_t argz_create (char *const argv[], char **argz, size t *argz_len)
error_t argz_create_sep (const char *string, int sep, char **argz, size t *argz_len)
size_t argz_count (const char *argz, size t argz_len)
void argz_extract (const char *argz, size t argz_len, char **argv)
void argz_stringify(char *argz, size t len, int sep)
error_t argz_add (char **argz, size t *argz_len, const char *str)
error_t argz_add_sep (char **argz, size t *argz_len, const char *str, int delim)
error_t argz_append (char **argz, size t *argz_len, const char *buf, size t buf_len)
void argz_delete (char **argz, size t *argz_len, char *entry)
error_t argz_insert (char **argz, size t *argz_len, char *before, const char *entry)
char * argz_next (const char *argz, size t argz_len, const char *entry)
error_t argz_replace (char **argz, size t *argz_len, const char *str, const char *with, unsigned *replace_count)
char * envz_entry (const char *envz, size t envz_len, const char *name)
char * envz_get (const char *envz, size t envz_len, const char *name)
error_t envz_add (char **envz, size t *envz_len, const char *name, const char *value)
error_t envz_merge (char **envz, size t *envz_len, const char *envz2, size t envz2_len, int override)
void envz_strip (char **envz, size t *envz_len)
void envz_remove (char **envz, size t *envz_len, const char *name)