Libxml problems

Question

Hi,
I am trying to use the libxml2 library, and cant manage to compile some example code from the documentation not sure what im doing wrong, but i haven't used gcc much before.
The code:
#include <stdio.h>
#include <libxml/xmlreader.h>
#ifdef LIBXML_READER_ENABLED
* processNode:
* @reader: the xmlReader
* Dump information about the current node
static void
processNode(xmlTextReaderPtr reader) {
const xmlChar *name, *value;
name = xmlTextReaderConstName(reader);
if (name == NULL)
name = BAD_CAST "--";
value = xmlTextReaderConstValue(reader);
printf("%d %d %s %d %d",
xmlTextReaderDepth(reader),
xmlTextReaderNodeType(reader),
name,
xmlTextReaderIsEmptyElement(reader),
xmlTextReaderHasValue(reader));
if (value == NULL)
printf("\n");
else {
if (xmlStrlen(value) > 40)
printf(" %.40s...\n", value);
else
printf(" %s\n", value);
* streamFile:
* @filename: the file name to parse
* Parse and print information about an XML file.
static void
streamFile(const char *filename) {
xmlTextReaderPtr reader;
int ret;
reader = xmlReaderForFile(filename, NULL, 0);
if (reader != NULL) {
ret = xmlTextReaderRead(reader);
while (ret == 1) {
processNode(reader);
ret = xmlTextReaderRead(reader);
xmlFreeTextReader(reader);
if (ret != 0) {
fprintf(stderr, "%s : failed to parse\n", filename);
} else {
fprintf(stderr, "Unable to open %s\n", filename);
int main(int argc, char **argv) {
if (argc != 2)
return(1);
* this initialize the library and check potential ABI mismatches
* between the version it was compiled for and the actual shared
* library used.
LIBXML_TEST_VERSION
streamFile(argv[1]);
* Cleanup function for the XML library.
xmlCleanupParser();
* this is to debug memory for regression tests
xmlMemoryDump();
return(0);
#else
int main(void) {
fprintf(stderr, "XInclude support not compiled in\n");
exit(1);
#endif
Im compiling as:
g++ -isystem /usr/include/libxml2 main.cpp
The libxml2 headers are stored here: /usr/include/libxml2/libxml/
And i get lots of undefined reference errors:
/tmp/ccuri8t3.o: In function `processNode(_xmlTextReader*)':
main.cpp:(.text+0x10): undefined reference to `xmlTextReaderConstName'
main.cpp:(.text+0x2b): undefined reference to `xmlTextReaderConstValue'
main.cpp:(.text+0x39): undefined reference to `xmlTextReaderHasValue'
main.cpp:(.text+0x46): undefined reference to `xmlTextReaderIsEmptyElement'
main.cpp:(.text+0x53): undefined reference to `xmlTextReaderNodeType'
main.cpp:(.text+0x60): undefined reference to `xmlTextReaderDepth'
main.cpp:(.text+0xa4): undefined reference to `xmlStrlen'
/tmp/ccuri8t3.o: In function `streamFile(char const*)':
main.cpp:(.text+0xff): undefined reference to `xmlReaderForFile'
main.cpp:(.text+0x113): undefined reference to `xmlTextReaderRead'
main.cpp:(.text+0x12e): undefined reference to `xmlTextReaderRead'
main.cpp:(.text+0x142): undefined reference to `xmlFreeTextReader'
/tmp/ccuri8t3.o: In function `main':
main.cpp:(.text+0x1b7): undefined reference to `xmlCheckVersion'
main.cpp:(.text+0x1cf): undefined reference to `xmlCleanupParser'
main.cpp:(.text+0x1d4): undefined reference to `xmlMemoryDump'
collect2: ld returned 1 exit status
Any ideas on what i am doing wrong? I suspect i havent told gcc how to use the headers correctly?
Thanks
Jack

Answer 1

you also need '''-I/usr/include/libxml2
-L/usr/lib -lxml2 -lz -lm'''
compile with g++ `xml2-config --cflags --libs` main.cpp == a.out