#!/usr/bin/env bash

# @(#) s1	Demonstrate extraction of external names.

# Uncomment to run script as external user.
# export PATH="/usr/local/bin:/usr/bin:/bin"
# Infrastructure details, environment, commands for forum posts. 
set +o nounset
pe() { for i;do printf "%s" "$i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
LC_ALL=C ; LANG=C ; export LC_ALL LANG
pe ; pe "Environment: LC_ALL = $LC_ALL, LANG = $LANG"
pe "(Versions displayed with local utility \"version\")"
c=$( ps | grep $$ | awk '{print $NF}' )
version >/dev/null 2>&1 && s=$(_eat $0 $1) || s=""
[ "$c" = "$s" ] && p="$s" || p="$c"
version >/dev/null 2>&1 && version "=o" $p specimen gfortran ar nm grep ftnchek ld
set -o nounset

# Sample data files, using head & tail as a last resort.
pe
specimen 7 *.f \
|| { pe "(head/tail)"; head -n 5 data*; pe " ||"; tail -n 5 data*; }

# Remove debris from previous runs.
rm -f *.o a.out *.a

pl " Results of compile, scan for externals::"
gfortran -c *.f

# Build the library.
ar sq libs.a libs.o

# Extract and display the symbols.
pl " Sample of nm output:"
# nm -fbsd main.o subs.o libs.a
# nm -fbsd -u main.o subs.o libs.a	# Unsatisfied only
# nm -fsysv main.o subs.o libs.a
nm -fposix main.o subs.o libs.a |
tee t1 | 
specimen 4

# Massage nm output to obtain entry points, "T", externals, "U".
awk '$2 == "T" { print $1 }' t1 > ent
awk '$2 == "U" { print $1 }' t1 > ext

pl " Non-system externals found:"
grep -v '^_' ext

pl " Unsatisfied externals in this application:"
# Remove matching entry-externals, remove system routines.
grep -v -f ent ext |
grep -v '^_'

pl " Results from ftnchek:"
ftnchek *.f

pl " Create link map from linker (ld):"
gfortran  -Wl,--print-map -Wl,--noinhibit-exec -o a.out main.o subs.o libs.a > map.txt
specimen 3 map.txt

pl " Results of execution:"
gfortran -Wl,--noinhibit-exec -o a.out main.o subs.o libs.a
./a.out

exit 0

% ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0 
GNU bash 3.2.39
specimen (local) 1.17
gfortran GNU Fortran (Debian 4.3.2-1.1) 4.3.2
GNU ar (GNU Binutils for Debian) 2.18.0.20080103
GNU nm (GNU Binutils for Debian) 2.18.0.20080103
GNU grep 2.5.3
FTNCHEK Version 3.3 November 2004 Patch Level 1
GNU ld (GNU Binutils for Debian) 2.18.0.20080103

Whole: 7:0:7 of 11 lines in file "libs.f"
	subroutine b
	call b1
	return
	end
	subroutine b1
	call b2
	return
	end
	subroutine b2
	return
	end

Whole: 7:0:7 of 13 lines in file "main.f"
	program m
	call a
	call b
	end
	subroutine a
	x = 4.0
	xo = a1(x)
	y = 9.0
	yo = a2(y)
	z = xo + yo
	write(*,*) " z is", z
	return
	end

Whole: 7:0:7 of 12 lines in file "subs.f"
	function a1(x)
	a1 = sqrt(x)
	return
	end
	function a2(y)
	if ( y .lt. 4.0 ) then
	a2 = cubert(y)
	else
	a2 = sqrt(y)
	endif
	return
	end

-----
 Results of compile, scan for externals::
ar: creating libs.a

-----
 Sample of nm output:
Edges: 4:0:4 of 20 lines in file "-"
main.o:
MAIN__ T 0000000000000000 0000000000000029
_gfortran_set_options U         
_gfortran_st_write U         
   ---
libs.a[libs.o]:
b1_ T 0000000000000010 0000000000000010
b2_ T 0000000000000020 0000000000000006
b_ T 0000000000000000 0000000000000010

-----
 Non-system externals found:
a1_
a2_
b_
cubert_

-----
 Unsatisfied externals in this application:
cubert_

-----
 Results from ftnchek:

FTNCHEK Version 3.3 November 2004

File libs.f:
 0 syntax errors detected in file libs.f
File main.f:
 0 syntax errors detected in file main.f
File subs.f:
 0 syntax errors detected in file subs.f
Warning: Subprogram CUBERT never defined
    Invoked in module A2 line 7 file subs.f
    (possibly it is an array which was not declared)

-----
 Create link map from linker (ld):
subs.o: In function `a2_':
subs.f:(.text+0x57): undefined reference to `cubert_'
Edges: 3:0:3 of 487 lines in file "map.txt"
Archive member included because of file (symbol)

libs.a(libs.o)                main.o (b_)
   ---
 *(.note.GNU-stack)
 *(.gnu_debuglink)
OUTPUT(a.out elf64-x86-64)

-----
 Results of execution:
subs.o: In function `a2_':
subs.f:(.text+0x57): undefined reference to `cubert_'
  z is   5.0000000