CTYPE.DOC (c)Copyright 1990, Matthew Dillon, All Rights Reserved TABLE OF CONTENTS c.lib/ctype/isalnum c.lib/ctype/isalpha c.lib/ctype/iscntrl c.lib/ctype/isdigit c.lib/ctype/isgraph c.lib/ctype/islower c.lib/ctype/isprint c.lib/ctype/ispunct c.lib/ctype/isspace c.lib/ctype/isupper c.lib/ctype/isxdigit c.lib/ctype/tolower c.lib/ctype/toupper ctype/isalnum ctype/isalnum NAME isalnum - check that a character is in the alpha numeric domain SYNOPSIS int r = isalnum(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is an alpha numeric (a-z, A-Z, 0-9), zero if it is not. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(isalnum('a')); assert(isalnum('Z')); assert(isalnum('1')); assert(!isalnum('%')); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/isalpha ctype/isalpha NAME isalpha - check that a character is in the alphabetic domain SYNOPSIS int r = isalpha(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is a letter in the alphabet (a-z, A-Z), zero if it is not. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(isalpha('a')); assert(isalpha('Z')); assert(!isalpha('1')); assert(!isalpha('%')); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/iscntrl ctype/iscntrl NAME iscntrl - check for a control character SYNOPSIS int r = iscntrl(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is a control character (0-31), zero if it is not. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(iscntrl(10)); assert(iscntrl(8)); assert(!iscntrl('1')); assert(!iscntrl('%')); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/isdigit ctype/isdigit NAME isdigit - check for a numeric character SYNOPSIS int r = isdigit(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is a digit ('0' through '9'), zero if it is not. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(isdigit('9')); assert(isdigit('0')); assert(!isdigit('x')); assert(!isdigit(7)); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/isgraph ctype/isgraph NAME isgraph - check for a printable character, excludes the space character SYNOPSIS int r = isgraph(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is printable and not a space, zero otherwise. This function is the isprint() function but with space character excluded from the printable set. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(isgraph('^')); assert(isgraph('$')); assert(!isgraph(' ')); assert(!isgraph(127)); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/islower ctype/islower NAME islower - check for a lower case alphabetic character SYNOPSIS int r = islower(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is a lower case letter 'a' - 'z', zero otherwise. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(islower('a')); assert(islower('g')); assert(!islower('Z')); assert(!islower(127)); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/isprint ctype/isprint NAME isprint - check for a printable character, includes the space character SYNOPSIS int r = isprint(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is printable, zero otherwise. This function is the isgraph() function but with space character included in the printable set. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(isprint(' ')); assert(isprint('^')); assert(!isprint(23)); assert(!isprint(127)); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/isupper ctype/isupper NAME isupper - check for an upper case alphabetic character SYNOPSIS int r = isupper(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character is an upper case letter 'A' - 'Z', zero otherwise. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(isupper('A')); assert(isupper('G')); assert(!isupper('z')); assert(!isupper(127)); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/isxdigit ctype/isxdigit NAME isxdigit - check for a character representable as a hexadecimal digit SYNOPSIS int r = isxdigit(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION Returns non-zero if the character represents a hexadecimal digit '0' - '9', 'a' - 'f', or 'A' - 'F', zero otherwise. NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { assert(isxdigit('9')); assert(isxdigit('0')); assert(isxdigit('A')); assert(isxdigit('d')); assert(!isxdigit('x')); assert(!isxdigit(27)); } INPUTS int c; character that we are checking RESULTS int r; 0 if the check failed, non-zero if the check is true SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/tolower ctype/tolower NAME tolower - converts a character into lower case SYNOPSIS int lc = tolower(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION If the character is in upper case the equivalent lower case character is returned, else the argument is returned (i.e. no change) NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { printf("%c%c%c%c", tolower('a'), tolower('B'), tolower('%'), tolower('Q')); } INPUTS int c; character that we are checking RESULTS int r; converted character SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper ctype/toupper ctype/toupper NAME toupper - converts a character into upper case SYNOPSIS int lc = toupper(c); int c; This is a MACRO if you #include , a subroutine call if you do not. FUNCTION If the character is in lower case the equivalent upper case character is returned, else the argument is returned (i.e. no change) NOTE When a non-zero value is returned, this value can be *anything* other than zero. It is not necessarily a 1. It is guarenteed to fit in a short, however, and still remain non-zero. characters in the 128-255 range are valid inputs. characters less than -1 or larger than 255 are ILLEGAL and the results will be random. If you are passing a CHAR, you must cast it to an UNSIGNED CHAR first. EOF is a valid input an always returns false EXAMPLE #include #include main() { printf("%c%c%c%c", toupper('a'), toupper('B'), toupper('%'), toupper('Q')); } INPUTS int c; character that we are checking RESULTS int r; converted character SEE ALSO isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper