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authorHeinrich Schuchardt <xypron.glpk@gmx.de>2018-07-29 11:08:14 +0200
committerTom Rini <trini@konsulko.com>2018-08-10 13:45:32 -0400
commit1b04047a875e8f3da78417c1a7f232e12490436d (patch)
tree7744e13175078a08ea4daa9202636a84f5a421db /README
parent938b05a5d796045a93a98ec17606c434c1339881 (diff)
downloadu-boot-1b04047a875e8f3da78417c1a7f232e12490436d.tar.gz
README: U_BOOT_ENV_CALLBACK functions
Describe the interface of environment variable callback functions. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
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@@ -3943,6 +3943,17 @@ If CONFIG_REGEX is defined, the variable_name above is evaluated as a
regular expression. This allows multiple variables to be connected to
the same callback without explicitly listing them all out.
+The signature of the callback functions is:
+
+ int callback(const char *name, const char *value, enum env_op op, int flags)
+
+* name - changed environment variable
+* value - new value of the environment variable
+* op - operation (create, overwrite, or delete)
+* flags - attributes of the environment variable change, see flags H_* in
+ include/search.h
+
+The return value is 0 if the variable change is accepted and 1 otherwise.
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