g++ flags post

content/post/20220301-gcc-flags/index.md

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+title = "My Favorite g++ Flags for a New Project"
+date = 2022-03-02T00:00:00
+lastmod = 2022-03-02T00:00:00
+draft = false
+
+# Authors. Comma separated list, e.g. `["Bob Smith", "David Jones"]`.
+authors = ["Carl Pearson"]
+
+tags = ["C++"]
+
+summary = "C++ is hard; make it a bit easier."
+
+# Projects (optional).
+#   Associate this post with one or more of your projects.
+#   Simply enter your project's folder or file name without extension.
+#   E.g. `projects = ["deep-learning"]` references 
+#   `content/project/deep-learning/index.md`.
+#   Otherwise, set `projects = []`.
+projects = []
+
+# Featured image
+# To use, add an image named `featured.jpg/png` to your project's folder. 
+[image]
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+  caption = ""
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+  focal_point = "Center"
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+  preview_only = true
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+
+categories = []
+
+# Set captions for image gallery.
+
+
++++
+
+The summaries are taken from https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
+
+* `-Wall`: turns on many warnings, but not "all."
+* `-Wextra`: turns on even more warnings, but still not all.
+* `-Wcast-align`: warn whenever a pointer is cast such that the required alignment is increased (`char*` -> `int*`).
+* `-Wcast-qual`: warn when qualifier (`cosnst`) is cast away, or introduces a qualifier in an unsafe way.
+* `-Wdisabled-optimization`: warn if a requested optimization pass is disable.
+* `-Wduplicated-branches`: warn if if-else branches have identical bodies
+* `-Wduplicated-cond`: warn about duplicated conditions in an if-else-if chain
+* `-Wformat=2`: same as `-Wformat` `-Wformat-nonliteral` `-Wformat-security` `-Wformat-y2k`. make sure printf-style function arguments match their format strings.
+* `-Wlogical-op`: warn about suspicious use of logical operators, i.e. contexts where bitwise is more likely.
+* `-Wmissing-include-dirs`: warn if a user-supplied include dir does not exist.
+* `-Wnull-dereference`: warn if paths that dereference a null pointer are detected
+* `-Woverloaded-virtual`: warn when a function declaration hides virtual functions from a base class
+* `-Wpointer-arith`: warn about `sizeof` for function types or `void`
+* `-Wshadow`: warn about variable shadowing and global function shadowing
+* `-Wswitch-enum`: warn when a `switch` on an enum type is missing one of the enums
+* `-Wvla`: warn about using variable-length arrays
+
+Also, in debug mode:
+
+* `-fasynchronous-unwind-tables`: allows stack unwinding from asycnrhonous events (https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html)
+
+## Honorable Mentions
+
+* `-fno-omit-frame-pointer`: g++ only turns on `-fomit-frame-pointer` on machines where it does not interfere with debugging, so no need for this one.
+* `-Wuseless-cast`: Warns when casting to the same type. Unfortunately, doesn't work well with MPI, since MPI_COMM_WORLD may be an int and casting it to MPI_Comm is a "useless cast"