问题
I got the following error on compiling a c code I wrote. I understand that the problem is in the header file. Can anyone please tell me which all header files are needed to define these functions.
sign.c: In function ‘main’:
sign.c:78: warning: assignment makes pointer from integer without a cast
/tmp/ccnsSeHy.o: In function `sign_data_evp':
sign.c:(.text+0x68): undefined reference to `check_ssl_rv'
sign.c:(.text+0xd5): undefined reference to `check_ssl_rv'
sign.c:(.text+0x13e): undefined reference to `check_ssl_rv'
/tmp/ccnsSeHy.o: In function `main':
sign.c:(.text+0x1ca): undefined reference to `initialize'
sign.c:(.text+0x1d6): undefined reference to `select_engine'
sign.c:(.text+0x20a): undefined reference to `sign_data'
sign.c:(.text+0x216): undefined reference to `clean_engine'
sign.c:(.text+0x21b): undefined reference to `clean_up'
collect2: ld returned 1 exit status
The header files that I have used so far is:
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <netdb.h>
#include <unistd.h>
#ifdef __VMS
#include <socket.h>
#include <inet.h>
#include <in.h>
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#endif
#include <openssl/crypto.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
Operating platform: Linux Thanks in advance.
回答1:
You understand it wrong. It does not complain about unknown function prototype, it complains during the linking. So you probably forgot to link with some library or some object file.
回答2:
try with this gcc sslprogname.c -o sslprogname -Wl,-Bstatic -lssl -Wl,-Bdynamic -lssl3 -lcrypto.It worked for me
来源：https://stackoverflow.com/questions/11135178/trouble-with-header-file