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C Library Functions  - regexec (3)

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NAME

regexec(3f) - [M_regex] Execute a compiled regex against a string

CONTENTS

Synopsis
Description
Options
Returns
Examples

SYNOPSIS

function regexec(this,string,matches,flags,status) result(match)

     logical :: match ! .TRUE. if the pattern matched
     type(regex_type),intent(in)           :: this
     character(len=*),intent(in)           :: string
     integer, intent(out),optional         :: matches(:,:)
     character(len=*),intent(in), optional :: flags
     integer, intent(out),optional         :: status

DESCRIPTION

OPTIONS

THIS	regex object
STRING	target string
MATCHES
	match locations dimension(2,*)
FLAGS	flag characters for partial lines: o b = no beginning-of-line (REG_NOTBOL) o e = no end-of-line (REG_NOTEOL)
STATUS	if absent, errors are fatal 0 successfully found match 1 successfully found no match other regexec(3f) failed

RETURNS

regexec
	LOGICAL value is .TRUE. if a match was found

EXAMPLES

Sample program

   program demo_regexec
   ! read regular expression from command line and look for it in lines read from stdin.
   use M_regex, only: regex_type, regcomp, regexec, regfree
   implicit none
   integer                      :: command_argument_length
   character(len=:),allocatable :: command_argument
   character(len=1024)          :: input_line
   type(regex_type)             :: regex
   logical                      :: match
   integer                      :: ios
      call get_command_argument(number=1,length=command_argument_length)
      allocate(character(len=command_argument_length) :: command_argument)
      call get_command_argument(1, command_argument)
      call regcomp(regex,command_argument,’xn’) ! compile up regular expression
      INFINITE: do
         read(*,’(a)’,iostat=ios)input_line
         if(ios.ne.0)exit INFINITE
         match=regexec(regex,input_line) ! look for a match in (remaining) string
         if(.not.match)cycle INFINITE    ! if no match found go for next line
         write(*,’(a)’) trim(input_line) ! show line with match
      enddo INFINITE
      call regfree(regex)                ! free memory used for compiled regular expression
   end program demo_regexec

Sample Output

     demo_regexec ’lt;integergt;’ < demo_regexec.f90
     integer                      :: command_argument_length
     integer                      :: ios

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Nemo Release 3.1

regexec (3)

June 29, 2025

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