Move logging functions to proj.h API

2 files changed, 78 insertions, 0 deletions

diff --git a/docs/source/development/reference/datatypes.rst b/docs/source/development/reference/datatypes.rst
index 8966923a..2a335a15 100644
--- a/docs/source/development/reference/datatypes.rst
+++ b/docs/source/development/reference/datatypes.rst
@@ -744,3 +744,53 @@ Info structures
     .. c:member:: char PJ_INIT_INFO.lastupdate
 
         Date of last update of the init-file.
+
+
+Logging
+-------------------------------------------------------------------------------
+
+.. c:type:: PJ_LOG_LEVEL
+
+    Enum of logging levels in PROJ. Used to set the logging level in PROJ.
+    Usually using :c:func:`proj_log_level`.
+
+    .. c:member:: PJ_LOG_NONE
+
+        Don't log anything.
+
+    .. c:member:: PJ_LOG_ERROR
+
+        Log only errors.
+
+    .. c:member:: PJ_LOG_DEBUG
+
+        Log errors and additional debug information.
+
+    .. c:member:: PJ_LOG_TRACE
+
+        Highest logging level. Log everything including very detailed debug
+        information.
+
+    .. c:member:: PJ_LOG_TELL
+
+        Special logging level that when used in :c:func:`proj_log_level`
+        will return the current logging level set in PROJ.
+
+    .. versionadded:: 5.1.0
+
+.. c:type:: PJ_LOG_FUNC
+
+    Function prototype for the logging function used by PROJ.
+    Defined as
+
+    .. code-block:: C
+
+        typedef void (*PJ_LOG_FUNCTION)(void *, int, const char *);
+
+    where the :c:type:`void` pointer references a data structure used by the
+    calling application, the :c:type:`int` is used to set the logging level
+    and the :c:type:`const char` pointer is the string that will be logged
+    by the function.
+
+
+    .. versionadded:: 5.1.0
diff --git a/docs/source/development/reference/functions.rst b/docs/source/development/reference/functions.rst
index 3d141ae2..52f801e5 100644
--- a/docs/source/development/reference/functions.rst
+++ b/docs/source/development/reference/functions.rst
@@ -276,6 +276,34 @@ Change the error-state of :c:data:`P` to `err`.
 
     .. note:: Available from version 5.1.0.
 
+
+Logging
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+.. c:function::  PJ_LOG_LEVEL proj_log_level (PJ_CONTEXT *ctx, PJ_LOG_LEVEL level)
+
+    Get and set logging level for a given context. Changes the log level to
+    :c:data:`level` and returns the previous logging level. If called with
+    :c:data:`level` set to :c:type:`PJ_LOG_TELL` the function returns the current
+    logging level without changing it.
+
+    :param PJ_CONTEXT* ctx: Threading context.
+    :param PJ_LOG_LEVEL level: New logging level.
+
+    :returns: :c:type:`PJ_LOG_LEVEL`
+
+    .. versionadded:: 5.1.0
+
+.. c:function::  void proj_log_func (PJ_CONTEXT *ctx, void *app_data, PJ_LOG_FUNCTION logf)
+
+    Override the internal log function of PROJ.
+
+    :param PJ_CONTEXT* ctx: Threading context.
+    :param void* app_data: Pointer to data structure used by the calling application.
+    :param PJ_LOG_FUNCTION logf: Log function that overrides the PROJ log function.
+
+    .. versionadded:: 5.1.0
+
 Info functions
 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++