82 lines
2.0 KiB
C++
82 lines
2.0 KiB
C++
/** @defgroup Utilities
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*
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* @brief Miscellaneous utilities.
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*
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* @{
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*/
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/** @file environ.hh
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*
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* @brief A portable environment variable interface.
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*
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* Provides utility functions to portably get, set and unset environment
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* variables.
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*
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* @copyright See COPYING.md in the project tree for further information.
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*/
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#ifndef OSTD_ENVIRON_HH
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#define OSTD_ENVIRON_HH
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#include <ostd/platform.hh>
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#include <ostd/string.hh>
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#include <optional>
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#include <string>
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namespace ostd {
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/** @addtogroup Utilities
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* @{
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*/
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/** @brief Gets an environment variable.
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*
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* @returns std::nullopt when the variable doesn't exist, and an std::string
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* containing the environment variable's value if it does.
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*
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* This function is thread-safe as long as the environment is not modified
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* within the program. Calling to lower level functions to set environment
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* vars as well as env_set() or env_unset() at the same time would introduce
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* potential data races.
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*
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* @see env_set(), env_unset()
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*/
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OSTD_EXPORT std::optional<std::string> env_get(string_range name);
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/** @brief Sets an environment variable.
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*
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* If `update` is false, the environment variable will not be overwritten
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* if it already exists. Keep in mind that true is still returned if the
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* variable already exists and it's not being updated.
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*
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* This function is not thread safe. Do not call it from multiple threads
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* and do not call it if a call to env_get() might be done from another
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* thread at the time.
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*
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* @returns true on success, false on failure.
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*
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* @see env_get(), env_unset()
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*/
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OSTD_EXPORT bool env_set(string_range name, string_range value, bool update = true);
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/** @brief Unsets an environment varible.
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*
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* This function is not thread safe. Do not call it from multiple threads
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* and do not call it if a call to env_get() might be done from another
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* thread at the time.
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*
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* @returns true on success, false on failure.
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*
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* @see env_get(), env_set()
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*/
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OSTD_EXPORT bool env_unset(string_range name);
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/** @} */
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} /* namespace ostd */
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#endif
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/** @} */
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