ranjanprj · November 9, 2019 18:10 · Nov 7, 2019 · Nov 7, 2019 · Nov 7, 2019 · Nov 7, 2019
diff --git a/PG_EXTN_C_WITH_RUST.md b/PG_EXTN_C_WITH_RUST.md
@@ -1,4 +1,4 @@
-# Just a small gist to show how you can easily you can create a Rust shared lib, wrap it with C and call it from PostgreSQL SQL Command.
+# Just a small gist to show how you can easily create a Rust shared lib, wrap it with C and call it from PostgreSQL SQL Command.
 
 0. Prereq : Tested on Ubuntu 18, GCC, postgresql-server-11, postgresql-dev-11, rustlang
 1. Create new project Cargo embed and cd embed

diff --git a/PG_EXTN_C_WITH_RUST.md b/PG_EXTN_C_WITH_RUST.md
@@ -38,7 +38,9 @@ double_num(PG_FUNCTION_ARGS)
 ```
 
 4. Create a file called Makefile in same folder
+*Please change the file path to point to your home directory*
 ```
+
 MODULES = funcs
 
 PG_CONFIG = pg_config
@@ -48,13 +50,15 @@ include $(PGXS)
 
 
 funcs.so: funcs.o
-        cc  -shared -o funcs.so funcs.o /home/ranjanprj/zig/libmathtest.so.0.0.0
+        cc  -shared -o funcs.so funcs.o /home/ranjanprj/embed/target/release/libembed.so
 
 funcs.o: funcs.c
         cc -o funcs.o -c funcs.c $(CFLAGS) -I$(INCLUDEDIR)
+
 ```
 5. `sudo make && sudo make install`
 6. In postgresql create the extension
+*Please change the file path to point to your home directory*
 ```sql
 drop function if exists double_num(integer);
 

diff --git a/PG_EXTN_C_WITH_RUST.md b/PG_EXTN_C_WITH_RUST.md
@@ -1,4 +1,4 @@
-# Just a small gist to show how you can easily you can create a Rust shared lib, wrap it with C and call it from PostgreSQL SQL # # # Command.
+# Just a small gist to show how you can easily you can create a Rust shared lib, wrap it with C and call it from PostgreSQL SQL Command.
 
 0. Prereq : Tested on Ubuntu 18, GCC, postgresql-server-11, postgresql-dev-11, rustlang
 1. Create new project Cargo embed and cd embed

diff --git a/PG_EXTN_C_WITH_RUST.md b/PG_EXTN_C_WITH_RUST.md
@@ -1,4 +1,4 @@
-#Just a small gist to show how you can easily you can create a Rust shared lib, wrap it with C and call it from PostgreSQL SQL #Command.
+# Just a small gist to show how you can easily you can create a Rust shared lib, wrap it with C and call it from PostgreSQL SQL # # # Command.
 
 0. Prereq : Tested on Ubuntu 18, GCC, postgresql-server-11, postgresql-dev-11, rustlang
 1. Create new project Cargo embed and cd embed

diff --git a/PG_EXTN_C_WITH_RUST.md b/PG_EXTN_C_WITH_RUST.md
@@ -1,3 +1,5 @@
+#Just a small gist to show how you can easily you can create a Rust shared lib, wrap it with C and call it from PostgreSQL SQL #Command.
+
 0. Prereq : Tested on Ubuntu 18, GCC, postgresql-server-11, postgresql-dev-11, rustlang
 1. Create new project Cargo embed and cd embed
 2. Rename the file src/main.rs to lib.rs

diff --git a/PG_EXTN_C_WITH_RUST.md b/PG_EXTN_C_WITH_RUST.md
@@ -1,6 +1,6 @@
-
-1. Create new project Cargo embed
-2. Rename the file embed/src/main.rs to lib.rs
+0. Prereq : Tested on Ubuntu 18, GCC, postgresql-server-11, postgresql-dev-11, rustlang
+1. Create new project Cargo embed and cd embed
+2. Rename the file src/main.rs to lib.rs
 3. Add following code 
 ```
 #[no_mangle]
@@ -10,7 +10,7 @@ pub extern fn double_input(input: i32) -> i32 {
 
 ```
 
-3. Create a c file called funcs.c add following code
+3. Create a c file called funcs.c add following code in embed folder
 ```C
 
 #include "postgres.h"
@@ -35,7 +35,7 @@ double_num(PG_FUNCTION_ARGS)
 }
 ```
 
-4. Makefile
+4. Create a file called Makefile in same folder
 ```
 MODULES = funcs
 

diff --git a/PG_EXTN_C_WITH_RUST.md b/PG_EXTN_C_WITH_RUST.md
@@ -32,6 +32,7 @@ double_num(PG_FUNCTION_ARGS)
     int32   arg = PG_GETARG_INT32(0);
 
     PG_RETURN_INT32(double_input(arg));
+}
 ```
 
 4. Makefile

diff --git a/gistfile1.txt → PG_EXTN_C_WITH_RUST.md b/gistfile1.txt → PG_EXTN_C_WITH_RUST.md
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,68 @@
+
+1. Create new project Cargo embed
+2. Rename the file embed/src/main.rs to lib.rs
+3. Add following code 
+```
+#[no_mangle]
+pub extern fn double_input(input: i32) -> i32 {
+    input * 2
+}
+
+```
+
+3. Create a c file called funcs.c add following code
+```C
+
+#include "postgres.h"
+#include <string.h>
+#include "fmgr.h"
+#include "utils/geo_decls.h"
+
+#ifdef PG_MODULE_MAGIC
+PG_MODULE_MAGIC;
+#endif
+
+/* by value */
+extern int32_t double_input(int32_t input);
+PG_FUNCTION_INFO_V1(double_num);
+
+Datum
+double_num(PG_FUNCTION_ARGS)
+{
+    int32   arg = PG_GETARG_INT32(0);
+
+    PG_RETURN_INT32(double_input(arg));
+```
+
+4. Makefile
+```
+MODULES = funcs
+
+PG_CONFIG = pg_config
+PGXS = $(shell $(PG_CONFIG) --pgxs)
+INCLUDEDIR = $(shell $(PG_CONFIG) --includedir-server)
+include $(PGXS)
+
+
+funcs.so: funcs.o
+        cc  -shared -o funcs.so funcs.o /home/ranjanprj/zig/libmathtest.so.0.0.0
+
+funcs.o: funcs.c
+        cc -o funcs.o -c funcs.c $(CFLAGS) -I$(INCLUDEDIR)
+```
+5. `sudo make && sudo make install`
+6. In postgresql create the extension
+```sql
+drop function if exists double_num(integer);
+
+CREATE or replace FUNCTION double_num(integer) RETURNS integer
+     AS '/home/ranjanprj/embed/funcs.so', 'double_num'
+     LANGUAGE C STRICT;   
+
+
+```
+
+7. Execute 
+```sql
+select double_num(4);
+```
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