diff options
| -rw-r--r-- | configure.ac | 23 | ||||
| -rw-r--r-- | docs/INSTALL | 26 | ||||
| -rw-r--r-- | include/curl/curl.h | 12 |
3 files changed, 56 insertions, 5 deletions
diff --git a/configure.ac b/configure.ac index 41ebf6000..bb44612cf 100644 --- a/configure.ac +++ b/configure.ac @@ -1954,6 +1954,29 @@ AC_HELP_STRING([--disable-cookies],[Disable cookies support]), AC_MSG_RESULT(yes) ) +dnl ************************************************************ +dnl Enable hiding of internal symbols in library to reduce its size and +dnl speed dynamic linking of applications. This currently is only supported +dnl on gcc >= 4.0 +dnl +AC_MSG_CHECKING([whether to enable hidden symbols in the library]) +AC_ARG_ENABLE(hidden-symbols, +AC_HELP_STRING([--enable-hidden-symbols],[Hide internal symbols in library (gcc>=4)]) +AC_HELP_STRING([--disable-hidden-symbols],[Leave all symbols with default visibility in library]), +[ case "$enableval" in + no) + AC_MSG_RESULT(no) + ;; + *) AC_MSG_RESULT(yes) + AC_DEFINE(CURL_HIDDEN_SYMBOLS, 1, [to enable hidden symbols]) + AC_SUBST(CURL_HIDDEN_SYMBOLS) + CFLAGS="$CFLAGS -fvisibility=hidden" + ;; + esac ], + AC_MSG_RESULT(no) +) + +dnl ************************************************************ if test "x$ws2" = "xyes"; then dnl If ws2_32 is wanted, make sure it is the _last_ lib in LIBS (makes diff --git a/docs/INSTALL b/docs/INSTALL index b44168051..c892283b2 100644 --- a/docs/INSTALL +++ b/docs/INSTALL @@ -506,13 +506,17 @@ CROSS COMPILE ./configure --host=ARCH-OS +REDUCING SIZE +============= + There are a number of configure options that can be used to reduce the size of libcurl for embedded applications where binary size is an - important factor. First, be sure to set the CFLAGS environment variable - when configuring with any compiler optimization flags to reduce the - size of the binary. For gcc, this would mean at minimum: + important factor. First, be sure to set the CFLAGS variable when + configuring with any relevant compiler optimization flags to reduce the + size of the binary. For gcc, this would mean at minimum the -Os option + and probably the -march=X option as well, e.g.: - env CFLAGS='-Os' ./configure ... + ./configure CFLAGS='-Os' ... Be sure to specify as many --disable- and --without- flags on the configure command-line as you can to disable all the libcurl features that you @@ -526,10 +530,24 @@ CROSS COMPILE --disable-crypto-auth (disables HTTP cryptographic authentication) --disable-ipv6 (disables support for IPv6) --disable-verbose (eliminates debugging strings and error code strings) + --enable-hidden-symbols (eliminates unneeded symbols in library) --without-libidn (disables support for the libidn DNS library) --without-ssl (disables support for SSL/TLS) --without-zlib (disables support for on-the-fly decompression) + The GNU linker has a number of options to reduce the size of the libcurl + dynamic libraries on some platforms even further. Specify them by giving + the options -Wl,-Bsymbolic and -Wl,-s on the gcc command-line. + Be sure also to strip debugging symbols from your binaries after + compiling using 'strip' (or the appropriate variant if cross-compiling). + If space is really tight, you may be able to remove some unneeded + sections of the library using the -R option to objcopy (e.g. the + .comment section). + + Using these techniques it is possible to create an HTTP-only shared + libcurl library for i386 Linux platforms that is less than 90 KB in + size (as of version 7.15.4). + You may find that statically linking libcurl to your application will result in a lower total size. diff --git a/include/curl/curl.h b/include/curl/curl.h index 94c4551e0..bd9236ed3 100644 --- a/include/curl/curl.h +++ b/include/curl/curl.h @@ -58,7 +58,17 @@ extern "C" { #define CURL_EXTERN __declspec(dllimport) #endif #else -#define CURL_EXTERN + +#ifdef CURL_HIDDEN_SYMBOLS +/* + * On gcc >= 4 if -fvisibility=hidden is given then this is used to cause + * external definitions to be put into the shared library. It makes no + * difference to applications whether this is set or not, only the library. + */ +#define CURL_EXTERN __attribute__ ((visibility ("default"))) +#else +#define CURL_EXTERN +#endif #endif /* |