pkg-config gives invalid gcc and clang XMLSEC_CRYPTO definition

[lsh123]

* Tom Burdick [reporter] 2014-07-29 20:17:50 UTC*

When attempting to compile my own xmlsec based library and the examples and directly using the pkg-config flags the XMLSEC_CRYPTO definition causes errors due to the quote escaping. This is with xmlsec 1.2.20 on archlinux (no patches)

This is particularly frustrating at the moment as I'm writing a Go binding to libxml/libxslt/xmlsec and Go does not let me do anything to modify the results of pkg-config output when doing its thing.

GCC 4.9.1 Output:

gcc $(pkg-config --cflags --libs xmlsec1) sign1.c -o sign1                                                                                                                        :(
<command-line>:0:16: warning: missing terminating " character
sign1.c: In function ‘main’:
sign1.c:93:5: error: stray ‘\’ in program
     if(xmlSecCryptoDLLoadLibrary(BAD_CAST XMLSEC_CRYPTO) < 0) {
     ^
sign1.c:93:5: error: missing terminating " character
sign1.c:93:56: error: expected expression before ‘)’ token
     if(xmlSecCryptoDLLoadLibrary(BAD_CAST XMLSEC_CRYPTO) < 0) {
                                                        ^

clang 3.4.2 Output:

clang $(pkg-config --cflags --libs xmlsec1) sign1.c -o sign1                                                                                                                      :(
In file included from <built-in>:161:
<command line>:1:24: warning: missing terminating '"' character [-Winvalid-pp-token]
#define XMLSEC_CRYPTO \"openssl\"
                       ^
sign1.c:93:43: error: expected expression
    if(xmlSecCryptoDLLoadLibrary(BAD_CAST XMLSEC_CRYPTO) < 0) {
                                          ^
<command line>:1:23: note: expanded from here
#define XMLSEC_CRYPTO \"openssl\"
                      ^
sign1.c:184:43: warning: passing 'const char *' to parameter of type 'const xmlChar *' (aka 'const unsigned char *') converts between pointers to integer types with different sign [-Wpointer-sign]
    if(xmlSecKeySetName(dsigCtx->signKey, key_file) < 0) {
                                          ^~~~~~~~
/usr/include/xmlsec1/xmlsec/keys.h:197:73: note: passing argument to parameter 'name' here
                                                         const xmlChar* name);
                                                                        ^
2 warnings and 1 error generated.
1 tburdick@rocket ~/src/xmlsec/examples (git)-[master] % clang --version                                                                                                                                                                   :(
clang version 3.4.2 (tags/RELEASE_34/dot2-final)
Target: x86_64-unknown-linux-gnu
Thread model: posix

Go output for my bindings:

go build
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
# github.com/bfrog/xml
<command-line>:0:16: warning: missing terminating " character
./xml.c: In function ‘init’:
./xml.c:43:5: error: stray ‘\’ in program
     if(xmlSecCryptoDLLoadLibrary(BAD_CAST XMLSEC_CRYPTO) < 0) {
     ^
./xml.c:43:5: error: missing terminating " character
./xml.c:43:56: error: expected expression before ‘)’ token
     if(xmlSecCryptoDLLoadLibrary(BAD_CAST XMLSEC_CRYPTO) < 0) {

                                                    ^

Any ideas on how to solve this in the meantime would be really appreciated, for my own purposes I just ended up sticking the string literal for now temporarily into xmlSecCryptoDLLoadLibrary("openssl") like so but that seems fragile

[reply] [−] Comment 1 Aleksey Sanin [xmlsec developer] 2014-08-04 16:04:34 UTC

The GCC error doesn't look like pkg-config problem and some clang errors look weird as well...

Unfortunately, I am not exactly sure what is the problem here. I've just tried on latest Ubuntu I have and it worked w/o problem. Do you have any problems running 'make' in the xmlsec1/examples folder?

[reply] [−] Comment 2 Tom Burdick [reporter] 2014-08-05 03:59:42 UTC

The makefile in the xmlsec/examples folder does something very different than what most users of pkg-config would be doing I'd think? Its assigning the results of a shell command to a variable first.

I unfortunately cannot do that with go as Cgo enforces some very specific meta comments in Go that let me do very little.

In either case even the pkg-config docs say to use pkg-config as I have here in their examples. I would think it should work.

It seems like maybe there's too many escapes or not enough escapes going on here?

http://golang.org/cmd/cgo/

http://people.freedesktop.org/~dbn/pkg-config-guide.html

Migrated from: https://bugzilla.gnome.org/show_bug.cgi?id=733935

[lsh123]

Fixed by getting rid of XMLSEC_CRYPTO define. There is no good way to handle string defines in pkg-config. This might create backward compatibility problems though I made an effort to make it an unlikely event. Plus I think it is a better way forward anyway

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