Merge branch 'master' into exists

wassup05 · web-flow · commit 029860fd5ae1 · 2025-08-11T00:24:13.000+05:30
diff --git a/doc/specs/stdlib_system.md b/doc/specs/stdlib_system.md
@@ -726,6 +726,80 @@ Subroutine
 
 ---
 
+## `get_cwd` - Gets the current working directory
+
+### Status
+
+Experimental
+
+### Description
+
+This subroutine retrieves the current working directory the running process is executing from.
+It is designed to work across multiple platforms. On Windows, paths with both forward `/` and backward `\` slashes are accepted.
+
+### Syntax
+
+`call [[stdlib_system(module):get_cwd(subroutine)]] (cwd [, err])`
+
+### Class
+
+Subroutine
+
+### Arguments
+
+`cwd`: Shall be a character string for receiving the path of the current working directory (cwd). It is an `intent(out)` argument.
+
+`err`(optional): Shall be of type `state_type`, and is used for error handling. It is an `intent(out)` argument.
+
+### Return values
+
+`err` is an optional state return flag. On error if not requested, an `FS_ERROR` will trigger an error stop.
+
+### Example
+
+```fortran
+{!example/system/example_cwd.f90!}
+```
+
+---
+
+## `set_cwd` - Sets the current working directory
+
+### Status
+
+Experimental
+
+### Description
+
+This subrotine sets the current working directory the process is executing from.
+It is designed to work across multiple platforms. On Windows, paths with both forward `/` and backward `\` slashes are accepted.
+
+### Syntax
+
+`call [[stdlib_system(module):set_cwd(subroutine)]] (path [, err])`
+
+### Class
+
+Subroutine
+
+### Arguments
+
+`path`: Shall be a character string containing the path of the directory. It is an `intent(in)` argument.
+
+`err`(optional): Shall be of type `state_type`, and is used for error handling. It is an `intent(out)` argument.
+
+### Return values
+
+`err` is an optional state return flag. On error if not requested, an `FS_ERROR` will trigger an error stop.
+
+### Example
+
+```fortran
+{!example/system/example_cwd.f90!}
+```
+
+---
+
 ## `exists` - Checks if a path exists in the filesystem
 
 ### Status
@@ -768,8 +842,6 @@ Function
 
 `err`(optional): It is an optional state return flag. If not requested and an error occurs, an `FS_ERROR` will trigger an error stop.
 
-### Example
-
 ```fortran
 {!example/system/example_exists.f90!}
 ```
@@ -812,6 +884,8 @@ None.
 {!example/system/example_null_device.f90!}
 ```
 
+---
+
 ## `delete_file` - Delete a file
 
 ### Status
@@ -853,6 +927,8 @@ The file is removed from the filesystem if the operation is successful. If the o
 {!example/system/example_delete_file.f90!}
 ```
 
+---
+
 ## `join_path` - Joins the provided paths according to the OS
 
 ### Status
@@ -915,6 +991,8 @@ The result is an `allocatable` character string or `type(string_type)`
 {!example/system/example_path_join.f90!}
 ```
 
+---
+
 ## `split_path` - splits a path immediately following the last separator
 
 ### Status
@@ -955,6 +1033,8 @@ The splitted path. `head` and `tail`.
 {!example/system/example_path_split_path.f90!}
 ```
 
+---
+
 ## `base_name` - The last part of a path
 
 ### Status
@@ -990,6 +1070,8 @@ A character string or `type(string_type)`.
 {!example/system/example_path_base_name.f90!}
 ```
 
+---
+
 ## `dir_name` - Everything except the last part of the path
 
 ### Status
diff --git a/example/system/CMakeLists.txt b/example/system/CMakeLists.txt
@@ -17,7 +17,8 @@ ADD_EXAMPLE(path_base_name)
 ADD_EXAMPLE(path_dir_name)
 ADD_EXAMPLE(make_directory)
 ADD_EXAMPLE(remove_directory)
+ADD_EXAMPLE(cwd)
 ADD_EXAMPLE(exists)
 ADD_EXAMPLE(is_regular_file)
 ADD_EXAMPLE(is_directory)
-ADD_EXAMPLE(is_symlink)
+ADD_EXAMPLE(is_symlink)
diff --git a/example/system/example_cwd.f90 b/example/system/example_cwd.f90
@@ -0,0 +1,32 @@
+! Illustrate the usage of `get_cwd`, `set_cwd`
+program example_cwd
+    use stdlib_system, only: get_cwd, set_cwd
+    use stdlib_error, only: state_type
+    implicit none 
+
+    character(len=:), allocatable :: path
+    type(state_type) :: err
+
+    call get_cwd(path, err)
+
+    if (err%error()) then
+        print *, "Error getting current working directory: "//err%print()
+    end if
+    
+    print *, "CWD: "//path
+
+    call set_cwd("./src", err)
+
+    if (err%error()) then
+        print *, "Error setting current working directory: "//err%print()
+    end if
+
+    call get_cwd(path, err)
+
+    if (err%error()) then
+        print *, "Error getting current working directory after using set_cwd: "//err%print()
+    end if
+    
+    print *, "CWD: "//path
+end program example_cwd
+
diff --git a/src/stdlib_system.F90 b/src/stdlib_system.F90
@@ -2,7 +2,7 @@ module stdlib_system
 use, intrinsic :: iso_c_binding, only : c_int, c_long, c_ptr, c_null_ptr, c_int64_t, c_size_t, &
     c_f_pointer
 use stdlib_kinds, only: int64, dp, c_bool, c_char
-use stdlib_strings, only: to_c_char, find
+use stdlib_strings, only: to_c_char, find, to_string
 use stdlib_string_type, only: string_type
 use stdlib_optval, only: optval
 use stdlib_error, only: state_type, STDLIB_SUCCESS, STDLIB_FS_ERROR
@@ -159,6 +159,32 @@ module stdlib_system
 !!
 public :: remove_directory
 
+!! version: experimental
+!!
+!! Gets the current working directory of the process
+!! ([Specification](../page/specs/stdlib_system.html#get_cwd))
+!!
+!! ### Summary
+!! Gets the current working directory.
+!!
+!! ### Description
+!! This subroutine gets the current working directory the process is executing from.
+!!
+public :: get_cwd
+
+!! version: experimental
+!!
+!! Sets the current working directory of the process
+!! ([Specification](../page/specs/stdlib_system.html#set_cwd))
+!!
+!! ### Summary
+!! Changes the current working directory to the one specified.
+!!
+!! ### Description
+!! This subroutine sets the current working directory the process is executing from.
+!!
+public :: set_cwd
+
 !! version: experimental
 !!
 !! Deletes a specified file from the filesystem.
@@ -971,6 +997,25 @@ end function stdlib_is_directory
     
 end function is_directory
 
+! A Helper function to convert C character arrays to Fortran character strings
+function to_f_char(c_str_ptr, len) result(f_str)
+    type(c_ptr), intent(in) :: c_str_ptr
+    ! length of the string excluding the null character
+    integer(kind=c_size_t), intent(in) :: len
+    character(:), allocatable :: f_str
+
+    integer :: i
+    character(kind=c_char), pointer :: c_str(:)
+
+    call c_f_pointer(c_str_ptr, c_str, [len])
+
+    allocate(character(len=len) :: f_str)
+
+    do concurrent (i=1:len)
+        f_str(i:i) = c_str(i)
+    end do
+end function to_f_char
+
 ! A helper function to get the string describing an error from C functions.
 ! If `winapi` is  false or not present, uses `strerror` provided by `<string.h>`
 ! Otherwise, uses `strerror` on unix and `FormatMessageA` on windows.
@@ -996,13 +1041,7 @@ end function strerror
 
     c_str_ptr = strerror(len, winapi_)
 
-    call c_f_pointer(c_str_ptr, c_str, [len])
-
-    allocate(character(len=len) :: str)
-
-    do concurrent (i=1:len)
-        str(i:i) = c_str(i)
-    end do
+    str = to_f_char(c_str_ptr, len)
 end function c_get_strerror
 
 !! makes an empty directory
@@ -1104,6 +1143,56 @@ end function stdlib_remove_directory
 
 end subroutine remove_directory
 
+subroutine get_cwd(cwd, err)
+    character(:), allocatable, intent(out) :: cwd
+    type(state_type), optional, intent(out) :: err
+    type(state_type) :: err0
+
+    interface
+        type(c_ptr) function stdlib_get_cwd(len, stat) bind(C, name='stdlib_get_cwd')
+            import c_ptr, c_size_t
+            integer(c_size_t), intent(out) :: len
+            integer :: stat
+        end function stdlib_get_cwd
+    end interface
+
+    type(c_ptr) :: c_str_ptr
+    integer(c_size_t) :: len
+    integer :: stat
+
+    c_str_ptr = stdlib_get_cwd(len, stat)
+
+    if (stat /= 0) then
+        err0 = FS_ERROR_CODE(stat, c_get_strerror())
+        call err0%handle(err)
+    end if
+
+    cwd = to_f_char(c_str_ptr, len)
+
+end subroutine get_cwd
+
+subroutine set_cwd(path, err)
+    character(len=*), intent(in) :: path
+    type(state_type), optional, intent(out) :: err
+    type(state_type) :: err0
+
+    interface
+        integer function stdlib_set_cwd(path) bind(C, name='stdlib_set_cwd')
+            import c_char
+            character(kind=c_char), intent(in) :: path(*)
+        end function stdlib_set_cwd
+    end interface
+
+    integer :: code
+
+    code = stdlib_set_cwd(to_c_char(trim(path)))
+
+    if (code /= 0) then
+        err0 = FS_ERROR_CODE(code, c_get_strerror())
+        call err0%handle(err)
+    end if
+end subroutine set_cwd
+
 !> Returns the file path of the null device for the current operating system.
 !>
 !> Version: Helper function.
@@ -1122,21 +1211,13 @@ end function process_null_device
         
     end interface
     
-    integer(c_size_t) :: i, len
+    integer(c_size_t) :: len
     type(c_ptr) :: c_path_ptr
-    character(kind=c_char), pointer :: c_path(:)    
 
     ! Call the C function to get the null device path and its length
     c_path_ptr = process_null_device(len)
-    call c_f_pointer(c_path_ptr,c_path,[len])
 
-    ! Allocate the Fortran string with the length returned from C
-    allocate(character(len=len) :: path)
-        
-    do concurrent (i=1:len)
-        path(i:i) = c_path(i)
-    end do
-        
+    path = to_f_char(c_path_ptr, len)
 end function null_device
 
 !> Delete a file at the given path.
diff --git a/src/stdlib_system.c b/src/stdlib_system.c
diff --git a/test/system/test_filesystem.f90 b/test/system/test_filesystem.f90
