{"id":116,"date":"2026-10-12T08:31:20","date_gmt":"2026-10-12T08:31:20","guid":{"rendered":"http:\/\/www.scmgalaxy.com\/tutorials\/2009\/01\/29\/makefile\/"},"modified":"2026-10-12T08:31:20","modified_gmt":"2026-10-12T08:31:20","slug":"makefile","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/makefile\/","title":{"rendered":"Makefile Guide for C Libraries: Build Static and Shared Targets Cleanly"},"content":{"rendered":"\n

This guide explains a classic non-recursive Makefile<\/code> for a C project that builds both a static library (.a<\/code>) and a shared library (.so<\/code>). You will learn what each target does, how make<\/code> executes the workflow, and how to modernize the file while keeping its original intent.<\/p>\n\n\n\n

Originally published on 2009-01-29; fully revised and updated.<\/em><\/p>\n\n\n\n

\"makefile<\/figure>\n\n\n\n

What the original Makefile is doing<\/h2>\n\n\n\n

The original post shows an older, single-file build style: source files are listed directly, object files are derived from that list, and two library targets are built from the same objects. This is still a valid approach for small C projects.<\/p>\n\n\n

CC = gcc\nCFLAGS = -Wall -O2\nLFLAGS +=\n\nSRCS = cas.c \\\n       client.c \\\n       hashtable_itr.c\nOBJS = $(SRCS:.c=.o)\n\nall<\/span>: libmarquis.a libmarquis.so\n\nclean<\/span>:\n\\trm -f libmarquis.a libmarquis.so *.o\n\nlibmarquis.a: $(OBJS)\n\\tar -r $@ $(OBJS)\n\nlibmarquis.so: $(OBJS)\n\\t$(CC) -shared $(CFLAGS) -fPIC -Wl,-soname,libmarquis.so -o $@ $(OBJS)\n\n.c.o:\n\\t$(CC) $(CFLAGS) -c $<<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Important:<\/strong> recipe lines in a Makefile must begin with a real tab character. If tabs are converted to spaces, builds fail with a \u201cmissing separator\u201d error.<\/p>\n\n\n\n
Build workflow at a glance<\/h2>\n\n\n\n
\nflowchart TD\n    A[Run make all] --> B[Compile each C file into object file]\n    B --> C[Archive static library libmarquis.a]\n    B --> D[Link shared library libmarquis.so]\n    C --> E[Artifacts ready]\n    D --> E\n<\/pre>\n\n\n\n
Static vs shared library targets<\/h2>\n\n\n\n
Target<\/th>Output<\/th>Command style<\/th>Typical use<\/th><\/tr><\/thead>
libmarquis.a<\/code><\/td>Static archive<\/td>ar -r ...<\/code><\/td>Link code into binaries at build time<\/td><\/tr>
libmarquis.so<\/code><\/td>Shared object<\/td>gcc -shared ...<\/code><\/td>Load library dynamically at runtime<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
Useful commands while developing<\/h2>\n\n\n
# Build both outputs (default target)<\/span>\nmake\n\n# Build only the static library<\/span>\nmake libmarquis.a\n\n# Build only the shared library<\/span>\nmake libmarquis.so\n\n# Show commands without executing them<\/span>\nmake -n\n\n# Force rebuild of targets<\/span>\nmake -B\n\n# Remove generated artifacts<\/span>\nmake clean<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Modernized template with the same goals<\/h2>\n\n\n\n
The following version keeps the same intent, but uses a pattern rule, marks phony targets, and tracks header dependencies automatically.<\/p>\n\n\n
CC ?= gcc\nAR ?= ar\nCFLAGS ?= -Wall -O2\nCPPFLAGS ?=\nLDFLAGS ?=\n\nSRCS := cas.c client.c hashtable_itr.c\nOBJS<\/span> := $(SRCS:.c=.o)\nDEPS<\/span> := $(OBJS:.o=.d)\n\n.PHONY: all clean\nall<\/span>: libmarquis.a libmarquis.so\n\nlibmarquis.a: $(OBJS)\n\\t$(AR) rcs $@ $(OBJS)\n\nlibmarquis.so: $(OBJS)\n\\t$(CC) -shared -Wl,-soname,libmarquis.so -o $@ $(OBJS) $(LDFLAGS)\n\n%.o: %.c\n\\t$(CC) $(CPPFLAGS) $(CFLAGS) -fPIC -MMD -MP -c $< -o $@\n\nclean<\/span>:\n\\trm -f $(OBJS) $(DEPS) libmarquis.a libmarquis.so\n\n-include $(DEPS)<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Best practices<\/h2>\n\n\n\n
  • Keep target names predictable (all<\/code>, clean<\/code>, and output names).<\/li>
  • Use .PHONY<\/code> for non-file targets to avoid accidental conflicts.<\/li>
  • Prefer pattern rules (%.o: %.c<\/code>) over older suffix rules when maintaining or extending builds.<\/li>
  • Generate and include dependency files so header changes trigger correct rebuilds.<\/li>
  • Treat linker options (like -Wl,-soname,...<\/code>) as platform-specific and validate them in your CI environment.<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"
    This revised guide explains a classic C Makefile that builds both static and shared libraries. It breaks down each target, shows the build workflow, and provides a safer modern template you can adapt.<\/p>\n","protected":false},"author":1,"featured_media":3983,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[],"footnotes":""},"categories":[2],"tags":[2876,2971,2963,2967,2968,2965,2964,2969,2970,2966],"class_list":["post-116","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorised","tag-build-tool","tag-c-intro-project","tag-makefile","tag-makefile-example","tag-makefile-guide","tag-makefile-instruction","tag-makefile-overview","tag-makefile-tutorial","tag-simple-makefile","tag-what-is-makefile"],"_links":{"self":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/116","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/comments?post=116"}],"version-history":[{"count":3,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/116\/revisions"}],"predecessor-version":[{"id":78965,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/116\/revisions\/78965"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media\/3983"}],"wp:attachment":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media?parent=116"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/categories?post=116"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/tags?post=116"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}