| Defined in header <ctype.h> | ||||
|---|---|---|---|---|
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Converts the given character to lowercase according to the character conversion rules defined by the currently installed C locale.
In the default "C" locale, the following uppercase letters ABCDEFGHIJKLMNOPQRSTUVWXYZ are replaced with respective lowercase letters abcdefghijklmnopqrstuvwxyz.
Parameters
| ch | - | character to be converted. If the value of ch is not representable as unsigned char and does not equal EOF, the behavior is undefined. |
Return value
Lowercase version of ch or unmodified ch if no lowercase version is listed in the current C locale.
Example
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | #include <stdio.h>#include <ctype.h>#include <locale.h>#include <limits.h> int main(void){ /* In the default locale: */ unsigned char l; for (unsigned char u=0; u<UCHAR_MAX; u++) { l = tolower(u); if (l!=u) printf("%c%c ", u,l); } printf("\n\n"); unsigned char c = '\xb4'; // the character Ž in ISO-8859-15 // but ´ (acute accent) in ISO-8859-1 unsigned char c2 = c; // for printing setlocale(LC_ALL, "en_US.iso88591"); printf("in iso8859-1, tolower('0x%x') gives 0x%x\n", c2, tolower(c)); setlocale(LC_ALL, "en_US.iso885915"); printf("in iso8859-15, tolower('0x%x') gives 0x%x\n", c2, tolower(c));} |
Output:
1 2 3 4 | Aa Bb Cc Dd Ee Ff Gg Hh Ii Jj Kk Ll Mm Nn Oo Pp Qq Rr Ss Tt Uu Vv Ww Xx Yy Zz in iso8859-1, tolower('0xb4') gives 0xb4in iso8859-15, tolower('0xb4') gives 0xb8 |
References
- C11 standard (ISO/IEC 9899:2011):
- 7.4.2.1 The tolower function (p: 203)
- C99 standard (ISO/IEC 9899:1999):
- 7.4.2.1 The tolower function (p: 184)
- C89/C90 standard (ISO/IEC 9899:1990):
- 4.3.2.1 The tolower function
See also
| converts a character to uppercase (function) | |
| (C95) | converts a wide character to lowercase (function) |
C++ documentation for tolower | |
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