strchr

 

C

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Strings library

Null-terminated byte strings

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Null-terminated byte strings

Functions
Character manipulation
isalnum isalpha islower isupper isdigit isxdigit isblank (C99)	iscntrl isgraph isspace isprint ispunct tolower toupper
Conversions to and from numeric formats
atoiatolatoll (C99) atof strtolstrtoll (C99) strtoulstrtoull (C99)	strtoimaxstrtoumax (C99)(C99) strtofstrtodstrtold (C99)(C99) strfromfstrfromdstrfroml (C23)(C23)(C23)
String manipulation
strcpystrcpy_s (C11) strncpystrncpy_s (C11) strcatstrcat_s (C11)	strncatstrncat_s (C11) strxfrm strdup (C23) strndup (C23)
String examination
strlenstrnlen_s (C11) strcmp strncmp strcoll strchr strrchr	strspn strcspn strpbrk strstr strtokstrtok_s (C11)
Memory manipulation
memchr memcmp memsetmemset_explicitmemset_s (C23)(C11)	memcpymemcpy_s (C11) memmovememmove_s (C11) memccpy (C23)
Miscellaneous
strerrorstrerror_sstrerrorlen_s (C11)(C11)

 

Defined in header <string.h>
char* strchr( const char* str, int ch );	(1)
/*QChar*/ *strchr( /*QChar*/ *str, int ch );	(2)	(since C23)

1) Finds the first occurrence of ch (after conversion to char as if by (char)ch) in the null-terminated byte string pointed to by str (each character interpreted as unsigned char). The terminating null character is considered to be a part of the string and can be found when searching for '\0'.

2) Type-generic function equivalent to (1). Let T be an unqualified character object type.

• If str is of type const T*, the return type is const char*.
• Otherwise, if str is of type T*, the return type is char*.
• Otherwise, the behavior is undefined.

If a macro definition of each of these generic functions is suppressed to access an actual function (e.g. if (strchr) or a function pointer is used), the actual function declaration (1) becomes visible.

The behavior is undefined if str is not a pointer to a null-terminated byte string.

Parameters

str	-	pointer to the null-terminated byte string to be analyzed
ch	-	character to search for

Return value

Pointer to the found character in str, or null pointer if no such character is found.

Example

Run this code

#include <stdio.h>
#include <string.h>

int main(void)
{
    const char *str = "Try not. Do, or do not. There is no try.";
    char target = 'T';
    const char* result = str;

    while((result = strchr(result, target)) != NULL)
    {
        printf("Found '%c' starting at '%s'\n", target, result);
        ++result; // Increment result, otherwise we'll find target at the same location
    }
}

Output:

Found 'T' starting at 'Try not. Do, or do not. There is no try.'
Found 'T' starting at 'There is no try.'

References

• C23 standard (ISO/IEC 9899:2024):

• 7.24.5.2 The strchr function (p: TBD)

• C17 standard (ISO/IEC 9899:2018):

• 7.24.5.2 The strchr function (p: TBD)

• C11 standard (ISO/IEC 9899:2011):

• 7.24.5.2 The strchr function (p: 367-368)

• C99 standard (ISO/IEC 9899:1999):

• 7.21.5.2 The strchr function (p: 330)

• C89/C90 standard (ISO/IEC 9899:1990):

• 4.11.5.2 The strchr function

See also

memchr	searches an array for the first occurrence of a character (function)
strrchr	finds the last occurrence of a character (function)
strpbrk	finds the first location of any character in one string, in another string (function)
C++ documentation for strchr